Questions tagged [wireless-communication]

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13 views

Will a mobile phone (UE) in an LTE network not originate a call if signal strength is below a threshold (RSRP, RSRQ etc)?

What is the behaviour of a mobile phone (UE) in an LTE network if the measured signal strength of reference signals are low (RSRP, RSRQ) before call origination? Will the mobile attempt the call or ...
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41 views

Purpose of TV Towers at Present [closed]

We know that different communication towers exist around the world(e.g. Tokyo Tower). They are not only used as a TV tower but for radios and touristy purpose too. This is the age of dish antenna, ...
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8 views

Monitoring Connectivity on ZigBee

I am trying to figure out some ways in which a ZigBee network can be monitored. As is the case in any network, here we have a central coordinator and several slaves joined, however, there seems to be ...
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1answer
55 views

Was our wireless home telephone in the 1990s encrypted or completely insecure? And how did it work so far from home?

In the mid-1990s, our family got a cheap (I assume, since we weren't rich) but at least brand new telephone which either had two wireless "units", or one (my memory is a bit foggy on this detail), but ...
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3answers
60 views

Bandwidth vs Capacity

Two questions on wireless transmission, packed into one. First: I am confused about the meaning of the term 'Bandwidth' in a wireless transmission environment. The two most common definitions I could ...
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0answers
25 views

Intuitive interpretation of the U-shaped Jakes Spectrum

I was wondering if there is an intuitive interpretation for the Jakes spectrum? If I look at it in the time domain, which is basically the Bessel function zeroth order, it gives me a reading, how long ...
-1
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1answer
23 views

Small wireless proximity device to alert me when my cat gets into my WiFi range

I have the following situation. My cat goes outside every day, the problem is I have no way of telling when he is back around the house unless I go outside myself. I need some small wireless device I ...
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0answers
24 views

How I can controller the reach of WIFI antenna?

I would like to know, which antenna 802.11 model, it your reach can be controlled. In a some researches, I'm discovered a tool called "iwconfig", native on some Operation systems Unix Like. It is ...
2
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1answer
59 views

How can a Wi-Fi access point be visible from one device but not from another?

We have a strange issue while trying to configure small router for bridging between available access point and ethernet network. While this AP is perfectly visible from desktops and mobile devices, it ...
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32 views

What does this bandpass signal equation indicates?

This is the equation for bandpass signal from transmitter. What are the values for different parameters present in this equation. For example, what should be the value of P, Sl(t), Fc etc. Also what ...
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0answers
47 views

Is it better ASTRA 19.2°E or 28°, in central continental europe?

I'm trying to tune my satellite receiver, particularly to receive the signals of the Astra satellites, which are ASTRA 19.2E and ASTRA 2 at 28º East. Looking at the picture the signal from ASTRA 28 ...
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0answers
63 views

Spectral Efficiency of FDD, TDD, and FD

I would like to show at high level that, in principle, the spectral efficiency (SE) of frequency division duplex (FDD) equals the SE of time division duplex (TDD) and both of them are half the SE of ...
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0answers
39 views

Non Orthogonal Multiple Acess and Channel Quality Indicator

As we know in a 4G network, the LTE give us a correlation about the SNR of user and the data rate of the user. This correlation is usually a table called Channel Quality Indicator (CQI) which is found ...
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0answers
29 views

Mobile Frequency and Carrier Frequency not Matching

I am using a Google Nexus 6 Mobile in India with Airtel as Network Provider. Recently Airtel has upgraded their Network to 2300 Mhz 4G. Whereas Google Nexus 6 Operates on Band 3 (1800Mhz) LTE. When ...
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0answers
76 views

Negative transmit power in dBm

I am calculating the transmit power for $K$ single antenna IoT devices in an Indoor scenario. The receiver has 64 antennas. I am trying to minimize the transmit sum-power, i.e., $\sum_k p_k$, where $...
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29 views

what is the best way to communicate among multiple raspberry pi boards?

so i was planning to make a project were a system of computers( in my case raspberry pi's) need to communicate to do a certain job. And i am having a trouble choosing a way of communications. so i ...
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0answers
17 views

Modeling of a Wireless Channel with known BER

I have to model through software a wireless (my choice: 3g,4g, 802.11...) channel with given Bit Error Rate. I'm searching some distributions, I'm reading tons of papers but I can't find how to ...
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0answers
34 views

What's the best way to get an ultrasonic sensor that can vary its operating frequency

Long story short I'm looking to build an ultrasonic sensor that can also be used to communicate with a seperate sensor. (So it must be able to send out a pitch around ~42kHz, but also alter the pitch ...
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2answers
130 views

Can wider range (i.e. 600-700 MHz) antenna replace lower range (650-700 MHz) antenna?

I had an appliance (wireless audio receiver), which has operational range 662-698 mhz (and had same ranged antenna exactly from factory), like this: However, that antenna was broken accidentally and ...
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2answers
44 views

Most practical way to wirelessly transmit a single bit of information? [closed]

If I have a single Boolean value that I wish to transmit wirelessly over a relatively short distance (assume <2m) then what of the many possible options would be the most practical. To define what ...
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2answers
88 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....
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1answer
80 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
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 ...
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1answer
60 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
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1answer
437 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 ...
2
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2answers
94 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-...
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1answer
40 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 ...
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2answers
417 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 ...
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2answers
81 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 ...
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1answer
217 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
325 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?
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1answer
2k 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 ...
2
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2answers
116 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 ...
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2answers
100 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 ...
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4answers
353 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 ...
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1answer
4k 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
83 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
928 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
93 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
200 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
580 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
76 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
131 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, $...
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0answers
72 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
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1answer
99 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
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1answer
111 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 ...
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0answers
357 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
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0answers
107 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 ...
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0answers
536 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
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1answer
111 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 ...