Questions tagged [wireless-communication]

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9
votes
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 ...
7
votes
3answers
8k 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 ...
7
votes
0answers
534 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 ...
6
votes
1answer
128 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 ...
6
votes
0answers
544 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
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 ...
4
votes
1answer
162 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 ...
4
votes
1answer
83 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 ...
4
votes
1answer
640 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 ...
4
votes
0answers
75 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: ...
4
votes
1answer
216 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 ...
3
votes
2answers
167 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 ...
3
votes
1answer
938 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 ...
3
votes
1answer
868 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 ...
3
votes
1answer
640 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
votes
0answers
87 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
votes
0answers
133 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, $...
3
votes
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 ...
2
votes
1answer
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 ...
2
votes
1answer
33 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 ...
2
votes
1answer
101 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
votes
3answers
132 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 ...
2
votes
1answer
354 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?
2
votes
2answers
118 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 ...
2
votes
3answers
204 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 ...
2
votes
1answer
118 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 ...
2
votes
1answer
73 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 ...
2
votes
2answers
99 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-...
2
votes
0answers
31 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 ...
2
votes
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 ...
2
votes
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 ...
2
votes
0answers
105 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 $...
2
votes
1answer
90 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 "...
1
vote
4answers
367 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 ...
1
vote
2answers
45 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 ...
1
vote
1answer
41 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 ...
1
vote
1answer
107 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 ...
1
vote
1answer
58 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 ...
1
vote
1answer
132 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? ...
1
vote
0answers
20 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 ...
1
vote
0answers
52 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 ...
1
vote
0answers
11 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 ...
1
vote
0answers
28 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 ...
1
vote
0answers
150 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 ...
1
vote
0answers
107 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 ...
1
vote
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 ...
1
vote
0answers
35 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 ...
1
vote
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 ...
1
vote
1answer
255 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 ...
1
vote
0answers
390 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