Posts in Category: Course

What is Envelope Tracking? 

Posted by leopedrini Sunday, April 24, 2016 5:22:00 PM Categories: Course LTE RF Components
Perhaps you've heard that some mobile devices consume less or more battery than others. Or you may have heard the following: "When I put my mobile in LTE mode, it drains more battery." Unfortunately, this is true, especially in the case of LTE. This is one reason why the first LTE devices became known as 'bad' - battery drainer. Note: All telecomHall articles are originally written in Portuguese. Following we translate to English and Spanish. As our time is short, maybe you... read more

What are Modes, States and Transitions in GSM, UMTS and LTE? 

Posted by leopedrini Monday, April 04, 2016 4:00:00 PM Categories: Course LTE UMTS
Hello friends. Today we will talk about a very important issue for those working with mobile communications: what are the different modes and states that a mobile phone can take, as well as how the transitions occurs between each of them. The concept is simple, but the great amount of detail can end up making the topic an extensive or complex task. This ends up causing many people simply give up trying to understand, or even not to be interested about know such details. However, the lack... read more

What is CSFB and SRVCC in LTE? 

Posted by leopedrini Wednesday, May 20, 2015 9:19:00 AM Categories: Course CSFB IMS LTE SRVCC VoLTE
Regardless of the pace of LTE networks deployment around the world (faster in some areas, slower in others), the number of users with 4G devices is intensively growing. Thanks to factors such as lower costs - due to the gain of production scale, and also by encouraging migration to 4G plans - offered by operators who already have an available network, more and more people have access to new services and benefits that this technology offers. However, as much as the current data services... read more

What is CP (Cyclic Prefix) in LTE? 

Posted by leopedrini Thursday, November 13, 2014 1:40:00 PM Categories: Course LTE
Continuing the study of small (but important) LTE concepts, let's talk today about CP (Cyclic Prefix). Goal Our goal today is simple and straightforward: to understand what is the Cyclic Prefix (CP) and how it is used in LTE systems. // Note: All telecomHall articles are originally written in Portuguese. Following we translate to English and Spanish. As our time is short, maybe you find some typos (sometimes we just use the automatic translator, with only a final ... read more

What is LCS (and LBS)? 

Posted by leopedrini Thursday, November 13, 2014 7:10:00 AM Categories: Course
Probably you have already heard of LBS and LCS, but perhaps you did not associate those 'names' to the topic. And if you still do not work or deal with LCS/LBS, you will certainly do some day. Especially if you work in IT or Telecommunications area, where this subject is increasingly present. We're talking about location services. With the advance of services such M2M (Machine to Machine) and IoT (Internet of Things), location services are each day more present in our... read more

What does Orthogonal means in Wireless Networks?  

Posted by leopedrini Friday, October 31, 2014 1:06:00 PM Categories: Course
The orthogonality concept is one of the most important and crucial mechanisms that allow the existence of modern wireless systems such as WCDMA and LTE. But not always such a concept is understood with sufficient clarity, and ends up being just 'accepted'. // An example of this are the orthogonal codes - when it comes to CDMA and UMTS (WCDMA) we are already referring to them in the name of these access technologies itself. In LTE we also have the fundamental role of... read more

What is ISI (Inter Symbol Interference) in LTE? 

Posted by leopedrini Friday, February 28, 2014 1:04:00 PM Categories: Course LTE
The development of modulation techniques allowed significant developments in mobile communications through the transmission of symbols carrying a large amount of information. However, there is a common problem in such systems: the interference inter symbols (ISI or Inter Symbol Interference). Let us understand this today. // Note: All telecomHall articles are originally written in Portuguese. Following we translate to English and Spanish. As our time is... read more

What is Splitter and Combiner? 

RF Components - RF Power Divider and RF Power Combiner
Posted by leopedrini Wednesday, October 30, 2013 8:59:00 AM Categories: Course RF Components
To know the equipments used in your area and work, is a basic need of any professional. And understand its features and functions (applications) often represents the difference when getting a new job, or finding solutions to problems. In the Telecommunications & IT area we have a wide range of equipment (or components), which vary according to the specific area of expertise. For each of these equipment you can find a huge documentation available in the form of catalogs, courses, white... read more

Analyzing Coverage with Propagation Delay - PD and Timing Advance - TA (GSM-WCDMA-LTE) 

Posted by leopedrini Thursday, June 20, 2013 11:24:00 AM Categories: Course
One of the biggest challenges in Planning, Designing and even Optimization of Mobile Networks is to identify where the users are, or how they are distributed. Although this information is essential, it is not so easy to be obtained. But if we have and know how to use some counters related to this kind of analysis, everything is easier. For GSM, we have seen that we can have a good idea of the location (distribution) of users through the measures of TA (Timing Advance), as we detailed... read more

What is RRC and RAB? 

Posted by leopedrini Monday, May 20, 2013 11:21:00 AM Categories: Course
To work with modern wireless networks such as UMTS and LTE, it is essential that the telecom professional has full understanding of its basic concepts, such as those that control the call establishment and maintenance, whether it is voice (CS) or data (PS). In this scenario, RAB and RRC are two of the most important concepts because they are responsible for all the negotiation involved in those calls. // In addition to RAB and RRC, we still have some other terms... read more

What is Retransmission, ARQ and HARQ? 

Posted by leopedrini Friday, June 22, 2012 11:12:00 AM Categories: Course
It's very important to use solutions that improve the efficiency of the adopted model in any data communication system. If the transmission is 'Wireless', this need is even greater. In this scenario we have techniques that basically checks, or verify if the information sent by the transmitter correctly arrived in the receiver. In the following example, we have a packet being sent from the transmitter to the receiver. If the information arrived properly (complete), the receiver is ... read more

IP Packet switching in Telecom - Part 4 

Posted by leopedrini Thursday, March 22, 2012 11:11:00 AM Categories: Course
And then we finally get to NGN signaling protocols: SIP and SDP. The picture below was extracted from RFC 3261 and gives a fairly good example of a SIP dialog between two users, Alice and Bob. The entities involved in the call setup are called User Agents (UA). UAs which request services are called User Agent Clients (UAC), and those which fulfill requests are called User Agent Servers (UAS). Although the basic operating mode is end-to-end, the model supports the use of intermediate ... read more

IP Packet switching in Telecom - Part 3 

Posted by leopedrini Wednesday, February 15, 2012 10:08:00 AM Categories: Course
At the end of the precedent article I’ve told you that we’re going to dig a bit deeper into IMS and NGN signaling protocols (all this happens at the application layer of TCP/IP network architecture – see the first article of this series). Note: My blog Smolka et Catervarii (portuguese-only content for the moment) And so we shall do. I must warning you, though: you’d better fasten your seat belts, ‘cause there’s turbulence ahead. Few things can be more intellectually intimidating ... read more

IP Packet switching in Telecom - Part 2 

Posted by leopedrini Sunday, February 05, 2012 10:06:00 AM Categories: Course
So far so good… Like promised, let’s start our journey about IP networking in the telecom context from the ceiling and going down. So let’s understand what the heck is an “application”. Note: My blog Smolka et Catervarii (portuguese-only content for the moment) Technically we call an application any program that runs under control – and taking advantage of the services of – the operating system. That’s a fairly reasonable definition for our purposes, since all networking... read more

IP Packet switching in Telecom - Part 1 

Posted by leopedrini Monday, January 30, 2012 10:05:00 AM Categories: Course
Let me start saying thanks to Leonardo Pedrini for the privilege of writing this series of articles for TelecomHall. He doesn’t do this frequently that I know of. If you like the articles and want to read more then go visit my blog: Smolka et Catervarii (portuguese-only content for the moment). // I’d better warn you right now that you’ll find my writing style quite different from Leonardo’s. While he emphasizes simplicity I’m a bit more fond of rigorousness. So I’ll make ... read more

Goodbye IPv4... Hello IPv6! 

Posted by leopedrini Wednesday, November 09, 2011 9:54:00 AM Categories: Course
You've probably heard of IPv6. These little letters, increasingly known, will bring up a number of innovations and changes that should occur gradually over the World. // Changes that for sure will affect you, directly or indirectly - mainly due to the benefits that it provides. In Telecommunications area, the universe related to IPv6 is also increasingly in focus, and this subject for sure will be present to All of us in near future. So let's talk a little about... read more

What is Antenna Electrical and Mechanical Tilt (and How to use it)? 

Posted by leopedrini Thursday, October 13, 2011 11:09:00 AM Categories: Course
The efficiency of a cellular network depends of its correct configuration and adjustment of radiant systems: their transmit and receive antennas. And one of the more important system optimizations task is based on correct adjusting tilts, or the inclination of the antenna in relation to an axis. With the tilt, we direct irradiation further down (or higher), concentrating the energy in the new desired direction. When the antenna is tilted down, we call it 'downtilt', which is the most... read more

What is MIMO? 

Posted by leopedrini Thursday, September 08, 2011 11:01:00 AM Categories: Course
New technologies are increasingly present in our lives, evolving towards modern - and complicated - networks! To enable this 'Revolution', new techniques must be developed, and existing ones need to be improved. Here in telecomHall 'Course' we'll talk about these techniques, as always trying to explain each subject in the simplest possible way, allowing to understand how these innovations may have become reality. We begin today with: MIMO. Have you heard? // Even... read more

How to Run a RF Site Survey (Tips and Best Practices) 

Posted by leopedrini Monday, June 20, 2011 11:02:00 AM Categories: Course
From all the tasks that a telecommunication professional has, one of the most important is the RF Design. Mainly because this task results in physical changes in the network, by modifying or adding new sites and/or equipment. Based on the settings (and needs) of the current network, several areas - from Planning to Marketing and Optimization - may require changes to the these settings, that will define the future of the network. // Once defined the area of the new... read more

What is Ec/Io (and Eb/No)? 

Posted by leopedrini Tuesday, April 12, 2011 10:52:00 AM Categories: Course
If someone asks you "Which Signal Level for good call quality: -80 dbm or -90 dBm?" Beware, if you respond quickly, you might end up missing. This is because the correct answer is ... it depends! The Signal Strength is a very important and essential measure for any technology (GSM, CDMA, UMTS, LTE, etc.). However, it is not the only one: let's talk a little today about another magnitude, equally important: the Signal Noise Ratio. // Although this ratio is of fundamental... read more

What is Cellular Field Test Mode? 

Posted by leopedrini Monday, April 11, 2011 10:50:00 AM Categories: Course
The evaluation of the network through the phone's screen is possible using the feature known as a Field Test. // However, there is not much documentation available about this feature, so let's talk a bit about it today. Motivation Allow an IT and Telecom professional access network engineering information. What is Field Test? Field Test is also known as Test Mode, Engineering Mode, Net Monitor or some other similar variation. The mobile device... read more

What is Antenna? 

Posted by leopedrini Sunday, March 20, 2011 10:49:00 AM Categories: Course
If we only ask about the device, you'll know for sure to define what is an antenna, or at least have ever seen it. We also know that changing conditions or characteristics, for example targeting them, they improve the communication link. // But if someone asked to describe what is an antenna technically speaking, how would you describe its work? That's what we'll talk about today. Basics Before we begin to define the antenna work, we need to learn (or... read more

OSI 7 Layers Model 

Posted by leopedrini Monday, March 14, 2011 10:48:00 AM Categories: Course
When we started this tutorial, the intention was to talk about wireless physical and logical channels. In the course of the explanations, we realized it was necessary to first make an introduction for beginners, or even a brief review for those who already know: The Layers of the OSI Reference Model. // The Reference OSI layers Model (from now we'll just call OSI Model for short) is a very common term in Computer Networks and Wireless Systems, and its understanding can be... read more

What is RF Drive Test (Testing)? 

Posted by leopedrini Tuesday, March 08, 2011 9:46:00 AM Categories: Course
Every good RF design, after its implantation should be evaluated. There are few ways to do this, for example through analysis of KPI (Key Performance Indicator) or through prediction tools and signal interference. Other very common and efficient way to evaluate the network is conducting a Drive Test. But what is it? // The name is intuitive: take a drive test. The Drive Test is a test performed in cellular networks regardless of technology (GSM, CDMA, UMTS, LTE, etc. ...).... read more

What is Modulation? 

Posted by leopedrini Monday, February 28, 2011 9:44:00 AM Categories: Course
When we think about communication in a telecommunications system, the first thing that comes to mind is someone talking to another person. // Although it may seem simple, the transmission and reception of information is quite complex, considering the many possibilities and scenarios where this may occur. And one of the main schemes is involved in the modulation. So try to understand what it is today. Note: Our goal here is to be as simple and straightforward as... read more

What is Frequency Hopping - FHSS? 

Posted by leopedrini Thursday, February 24, 2011 9:42:00 AM Categories: Course
We can define Frequency Hopping as a communication scheme between a transmitter and a receiver. There are several concepts involved, such as spread spectrum modulation and switching frequency according to a known standard. // Frequency Hopping (FH) is widely used for example in GSM Networks, so let's understand a little more about it today. First, a Brief History But before we talk about FH: does who invented it? Several people competes for this title, as the... read more

What is Rake Receiver? 

Posted by leopedrini Tuesday, February 22, 2011 9:41:00 AM Categories: Course
Have you ever heard of "Rake Receiver"? Surely you've heard of Receiver (Receiver in English), and you probably have heard of Rake (Rake in English). With the pictures bellow, can you imagine what a Rake Receiver can be? Ok, if the analogy does not help much, let's go. // In a wireless communication system, the signal can reach the receiver via multiple distinct pathways. In each path, the signal can be blocked, reflected, diffracted and... read more

What is HSN and MAIO in GSM? 

Posted by leopedrini Sunday, February 06, 2011 9:40:00 AM Categories: Course
Today let's understand what are the parameters MAIO and HSN in a GSM network. The terms MAIO and HSN are also often used, but many people are confused about it's planning. That's right, HSN and MAIO are used in frequency planning of a GSM network, and know them well naturally will lead us to better results. // Quickly: The HSN is used to define the hopping sequence from one frequency list, and MAIO is used to set the initial frequency on this list. It did not help?... read more

What is RTWP? 

Posted by leopedrini Tuesday, February 01, 2011 9:39:00 AM Categories: Course
If you work with UMTS,'ve probably heard someone talk about RTWP. Its definition can be found in a dictionary of acronyms, such as Received Total Wideband Power. // Represents a measure of UMTS technology: the total level of noise within the UMTS frequency band of any cell. RTWP is related to uplink interference, and its monitoring helps control the call drops - mainly CS. It also has importance in the capacity management, as it provides... read more

Parameter Timing Advance (TA) 

Posted by leopedrini Friday, January 07, 2011 9:38:00 AM Categories: Course
The Timing Advance parameter is very important in many applications and procedures of the GSM system. // Let us understand what it is today, and know its main uses. What is Parameter Timing Advance (TA) in GSM? The Timing Advance is a parameter that allows the GSM BTS to control the signal delays in their communication with the mobile. More specifically, is calculated by the delay of information bits in Data Access Burst received by BTS. Recalling a little: ... read more

What is VSWR? 

Posted by leopedrini Tuesday, December 14, 2010 9:37:00 AM Categories: Course
Everyone has heard at least. Many knows that a bad VSWR affects the performance of the Network. But what about you: do you know what it means, and why we need to know how to use these measures? // Today we'll try to see a very simple way what is VSWR. VSWR To understand what is VSWR, we need to talk a little bit about signal propagation in radio frequency systems. Simply put, the radio frequency signals are driven by electric cables between transmitters /... read more

What is 0 dBm? 

Posted by leopedrini Friday, December 03, 2010 9:33:00 AM Categories: Course
Everyone who works with Telecom knows there is a relationship between Watts and dBm. But if the Power is expressed in Watts, why we must know - and use - this relationship in our day-to-day?? // Let's try to understand today in a simple manner, and discover why the use of decibels help us much. Watt (W) and miliWatt (mW) First of all, to understand what it means for example 0 dBm, we at least have to know the basic unit of power, the Watt. By definition, 1 Watt means ... read more