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Questions tagged [wireless-communication]

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1
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1answer
40 views

Tethered Balloons vs Towers for Wireless Communication

If we use tethered balloons (aerostats) with wireless gateways fitted on them (let's say for Cellular or LPWAN communication), they can provide much more coverage owing to the height they can reach (e....
2
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1answer
57 views

What criteria to focus on when selecting a BLE module?

I am trying to select a BLE module for low power application. I have looked into different BLE modules from different chip manufacturers. For example: ISM78G1D Bluetooth Low Energy SIP from Inventek ...
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0answers
11 views

During the GSM call flow when is the audio channel established?

I will like to know concretely when and how is the audio channel established to asses if it is possible that an eavesdropper can hear audio while the phone is ringing.
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0answers
14 views

Orthogonal Channels in a RAKE receiver?

Can I use the delay of different paths of a RAKE receiver for orthogonal channels. The idea is that if I have a square law detector for a packet of bits there will be no channel interference because ...
0
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1answer
54 views

dB/s/Hz in spectrum efficiency

Here is link of research paper in which spectrum efficiency is given in terms of dB/s/Hz. How can we define it? https://jwcn-eurasipjournals.springeropen.com/articles/10.1186/s13638-016-0792-0
3
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1answer
64 views

Making my microcontroller transmit audio to any bluetooth headphones/speakers

I am creating a microcontroller on a custom PCB design for an MP3 player. I would like to consider integrating bluetooth into it. When I say integrating bluetooth into it, I specifically mean ...
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0answers
10 views

Can dispersed in time radio signal be “assembled” together, to make it stronger and more efficient?

When the signal is transmitted, then aside of signal that gets directly to the receiver antenna, it propagates through many different stuff around. It scatters and depending on frequency it can be ...
1
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2answers
81 views

Can you detect the operation of a wireless radio (or other wavelength) receiver?

I am Comp-sci student doing a software engineering paper about designing a program, planning the software like you were actually planning a real-life software project, short of writing actual pseudo-...
1
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1answer
36 views

Why only the spectrum range of radio waves can be reflected from atmospheric layers while higher ranges (Infrared-Visible Light-Ultraviolet) can't?

From communication prospective why can't higher frequency ranges be reflected from atmospheric layers and what is the effect of parameters (like temperature, pressure, etc) of the atmospheric layer on ...
0
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2answers
126 views

Why does India have more than 1 MCC (Mobile Country Code)? [closed]

I was checking the list of MCC (Mobile Country Codes) on Wikipedia and found that India has two MCC: 404 and 405. 404 contains only GSM/UMTS/LTE operator bands and 405 contains both GSM/UMTS/LTE and ...
0
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2answers
72 views

How to decode radio thermometer / hygrometer bytes to floats?

I'm playing around with a radio receiver on 433MHz and I am receiving signals from a temperature / humidity sensor. I already figured out what bytes represent humidity, but I'm stuck with the ...
2
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1answer
145 views

What are alternative to installing LTE / Cell Tower to address capacity issue?

One of the cellular vendors wants to install a 180 foot monopole antenna in our neighborhood. They claim that there is significant growth in LTE consumers. So in order to better serve the customers ...
2
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1answer
164 views

A 40MHz oscillator in usb wifi adapter

I disassembled a usb wifi adapter. I was surprised to see a 40MHz oscillator, when wifi works at 2.4GHz. How the output of the oscillator is scaled to the required frequency?
5
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1answer
639 views

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 ...
3
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2answers
108 views

Why GPS receivers are more sensitive than GSM or WiFi receivers?

GPS receivers are able to operate at signal level of -150 dbm or less, but mobile phones need far more than -115 dbm level signal. Why GPS receivers are so much more sensitive than GSM or WiFi ...
0
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2answers
82 views

How can I make a GPS traceable microchip? [closed]

I am looking for making a chip or a microchip, which can be traced with the help of the satellites. Means it is merely a chip and when I tune my satellite to a particular frequency I would get to know ...
1
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4answers
350 views

How are three satellites sufficient to find a unique point in GPS? What happens in case of an overlap?

Consider: Is it because the 2nd and 3rd satellites' centres are collinear? Can a satellite overlap happen? If so then how is it avoided? If not avoided then what happen to the signal that is sent ...
9
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1answer
2k views

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 ...
2
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1answer
71 views

What is a multi-standard mcu?

I was watching a video on the ti products out currently for wireless microcontrollers, and they mentioned a "multi-standard" CC2650 mcu here http://bcove.me/uekqgi7q. What makes a microcontroller "...
2
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1answer
522 views

How to determine signal strength verses distance for LTE base stations?

All mobile phones have bars or some other type of indicator displaying signal strength. As mobile devices move away from the base station the signal strength becomes weak and at some point becomes out ...
2
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1answer
81 views

How can one determine the LTE base station providing service to a mobile device?

In order to have continuous service a mobile devices switches to base station with higher signal strength. Question: Is it possible using the mobile device (Android or iPhone) to determine to LTE ...
2
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3answers
184 views

Why not only GSM (3G/4G/..)? Why do we need Bluetooth, Wifi,etc…?

It is quite frustrating to have multiple adapter for connecting to desktop. For example, if I want to connect my phone to desktop I need Bluetooth/wifi; why can't I just just use the Mobile's main ...
3
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1answer
444 views

How to measure transmit power level from LTE base station?

Can someone tell me what type of equipment is used to measure RF power levels transmitted by a cellular LTE base station? I would like to gain some insight into how the follow data was obtained. ...
3
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0answers
68 views

Why don't cellphones use unidirectional antennas?

Why don't cellphones use unidirectional antennas instead of omnidirectional (single dipole) antennas? This could be accomplished by using a unidirectional array of dipole antennas (specifically, a ...
3
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0answers
115 views

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, $...
4
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0answers
57 views

Technical Analysis to determine optimal Cellular to transmitter location

At a very high level what are required technical analysis to determine the need to for a new 4G LTE cellular transmitter in US? find find the optimal location for the transmitter in US? Back Story: ...
1
vote
1answer
88 views

Interference between direct signal and reflected signal

A laptop's antenna receives signals from a Wi-Fi router in two ways: signal falling directly on the antenna from the router, say 1 m away signal coming from same router but bouncing off the ...
2
votes
1answer
97 views

Why is Li-Fi faster than regular wifi?

I was wondering, basicly every radio-transsmission works with electromagnetic waves which travels at the same speed whether I modulate the information with a low frequency or high frequency such as ...
1
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0answers
240 views

How can I increase my ultrasonic sensor accuracy?

I am using a long ranged ultrasonic sensor to measure milk height in milk silos. Milk is stirring. Milk Silos Design: Shows two type of silos both are stirred in different direction
3
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0answers
104 views

FM transmission exercise

I'm encountering some troubles while trying to solve this exercise. Let us consider a radio link between a geostationary satellite and a ground station. We send a binary signal (represented by two ...
7
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0answers
402 views

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 ...
5
votes
1answer
97 views

What is Byte Alignment Time in radio communication?

According to this paper, which deals with time synchronization in wireless networks, this kind of delay occurs, however I do not understand its explanation. The paper says the reciever (radio) has to ...
0
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1answer
60 views

how to calculate the time for retransmission in slotted Aloha

I need to configure my code to make retransmission in slotted Aloha in case of collision, how to choose the timer ?
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0answers
84 views

What is the carried load in pure aloha throughput equation

I made an enhancement on aloha protocol and I succeeded to decrease the total number of collided frames among the simulation time. Now, I need to calculate throughput to see if the number of ...
3
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1answer
740 views

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 ...
6
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0answers
372 views

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 ...
0
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1answer
323 views

What is the meaning of 'ergodic capacity' of a wireless communication channel?

I have a simple question: in the research literature on wireless communications I often see the term "Ergodic Capacity" of a channel. What does it mean?
4
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1answer
164 views

How do NFC/RFID devices transmit data?

I am designing an NFC device but am still a little unsure about the principles behind NFC/RFID. From what I understand: A primary coil constantly emits a 'carrier frequency' magnetic field. This ...
6
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2answers
5k views

How can I find the emission power of a WiFi mobile phone antenna?

I need to find the emission power of a WiFi mobile phone antenna. I have checked the IEEE 802.11 specifications but it says that the power transmission is variable and depends on the mobile phone ...
3
votes
1answer
128 views

How can I build an anti proximity alarm?

I am trying to build an alarm that works in an opposite way to a security alarm in a shop. In shops RF tags on items set off an alarm as you walk through a detector. I wanted to build alarm that ...
3
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1answer
578 views

TSOP IR receiver

I've been working with TSOP IR receivers and emitters on robots since the past year. With multiple robots communication we have signal collision algorithms and such. We still faced a lot of ...
1
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1answer
128 views

How to join between two PBX telephones wirelessly?

I have two PBX telephones. Each one has a line cables to the houses, but there is no connection between these two pbx telephones, neither wire nor wireless. How can I join between them wirelessly? ...