Questions tagged [wireless-communication]

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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 ...
user1558573's user avatar
8 votes
3 answers
10k 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 ...
agonza1's user avatar
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7 votes
0 answers
579 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 ...
Sara's user avatar
  • 81
6 votes
1 answer
144 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 ...
sifear's user avatar
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6 votes
0 answers
636 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 ...
Amesys's user avatar
  • 261
5 votes
1 answer
3k 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 ...
allanlaal's user avatar
  • 213
4 votes
1 answer
172 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 ...
user avatar
4 votes
2 answers
150 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 ...
Geremia's user avatar
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4 votes
1 answer
90 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 ...
Nil_2018's user avatar
  • 350
4 votes
1 answer
1k 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 ...
Trever Wagenhals's user avatar
4 votes
0 answers
88 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: ...
user7083's user avatar
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4 votes
1 answer
227 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 ...
Harry Smith's user avatar
3 votes
2 answers
266 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 ...
T.Todua's user avatar
  • 175
3 votes
1 answer
1k 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 ...
Tana's user avatar
  • 31
3 votes
1 answer
964 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 ...
Gaurav Roy's user avatar
3 votes
1 answer
797 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. ...
user7083's user avatar
  • 570
3 votes
0 answers
140 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, $...
Amesys's user avatar
  • 261
3 votes
0 answers
111 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 ...
hawake's user avatar
  • 31
2 votes
1 answer
1k 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 ...
user7083's user avatar
  • 570
2 votes
1 answer
36 views

Wireless communication modules transmitting through body

I wanted to be able to transmit data from a wireless module to an Arduino. It is possible that a human body could come between the wireless module and the Arduino or someone might cover up the module ...
Jeff Boker's user avatar
2 votes
1 answer
160 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 ...
user7083's user avatar
  • 570
2 votes
2 answers
883 views

Why do we always use 3.8 x 10^(-3) value as Forward Error Correction (FEC) threshold?

When we want to calculate the bit error rate (BER) for any communication system, why do we always select the 3.8 x 10-3 value as Forward Error Correction (FEC) threshold? Couldn't another value be ...
SH_IQ's user avatar
  • 121
2 votes
3 answers
749 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 ...
user27435's user avatar
2 votes
1 answer
423 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?
akm's user avatar
  • 265
2 votes
2 answers
209 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 ...
akm's user avatar
  • 265
2 votes
3 answers
223 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 ...
Googol Plex's user avatar
2 votes
1 answer
130 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 ...
user3921's user avatar
  • 123
2 votes
1 answer
76 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 ...
Andrey Sedelnikov's user avatar
2 votes
2 answers
115 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-...
torrey garcia's user avatar
2 votes
0 answers
86 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 ...
RolandM's user avatar
  • 21
2 votes
0 answers
41 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 ...
user avatar
2 votes
0 answers
171 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 $...
Chandan Pradhan's user avatar
2 votes
1 answer
94 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 "...
Perplexing Pies's user avatar
1 vote
4 answers
519 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 ...
Ayush N's user avatar
  • 27
1 vote
2 answers
80 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 ...
welf's user avatar
  • 488
1 vote
1 answer
42 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 ...
Mohamed Abdelkawy's user avatar
1 vote
1 answer
130 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 ...
akm's user avatar
  • 265
1 vote
1 answer
63 views

Do they sell some sort of non-"consumery" GPS trackers?

I have seen these expensive things that you can put in a moving box while moving, to keep track of your stuff in case the moving people drive away with their truck and steal it. I also see expensive ...
P. Yarborough's user avatar
1 vote
1 answer
139 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? ...
جمال الأحمد's user avatar
1 vote
0 answers
21 views

Transforming a Wireless Computer Mouse into a Wireless Switch [closed]

With no computer involved whatsoever, I want to be able to read oscillator outputs from my wireless mouse and switch an LED on a left click AND off on a right click. I have taken my mouse apart to try ...
Smartsav10's user avatar
1 vote
0 answers
154 views

Mesh Wifi Router Network for a Small Village

I was wondering if its possible to create mesh network of WiFi for relatively large area? I am talking about the size of small village (~20km2). The idea is to use centralized connectivity with enough ...
gijoe's user avatar
  • 83
1 vote
0 answers
12 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 ...
user27435's user avatar
1 vote
0 answers
32 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 ...
ayelsew's user avatar
  • 111
1 vote
0 answers
351 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 ...
Michaelangelo Meucci's user avatar
1 vote
0 answers
243 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 ...
Kotsos's user avatar
  • 111
1 vote
0 answers
31 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 ...
Mitesh Manani's user avatar
1 vote
0 answers
22 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 ...
Andrean's user avatar
  • 111
1 vote
0 answers
38 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 ...
haxonek's user avatar
  • 11
1 vote
0 answers
18 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 ...
user16118's user avatar
1 vote
1 answer
319 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 ...
user7083's user avatar
  • 570