LTE fundamentals


The fundamentals of the LTE Radio interface and get an overview of the evolution of 4G telecommunication. This 19 minutes video is presented by Ericsson expert Sven-Anders Sturesson.

The tutorial gives an overview of the fundamental technology of Long Term Evolution (LTE). You will learn the basics of the LTE radio interface, including multiple input, multiple outputs (MIMO), OFDM, uplink and downlink, SIMO, TDD, FDD, channel coding and GSA.

 

http://www.ericsson.com/ourportfolio/ericsson-academy/online-tutorials/lte_fundamentals_module/player.html



Source: Ericsson

What is Citrix ?

Citrix facilitates real-time access to shared applications over networks and the Internet. Remote access to Citrix-enabled applications can be over DSL, T1, ISDN, or dial-up. Citrix MetaFrame enables multiple users to run shared applications simultaneously. Communication between Citrix clients and servers consists of exchange of user inputs (keyboard/mouse) and screen shots. Citrix MetaFrame runs on Windows NT 4.0 (Terminal Server Edition) and Windows 2000, with Terminal Services installed.

Citrix products include:

  • Citrix Access Essentials
  • Citrix Access Gateway
  • Citrix Access Suite
  • Citrix Application Gateway
  • Citrix GoToAssist
  • Citrix GoToMeeting
  • Citrix GoToMyPC
  • Citrix NetScaler
  • Citrix Password Manager
  • Citrix Presentation Server

For technical support and questions regarding Citrix MetaFrame, go to http://support.citrix.com

Multimedia Broadcast Multicast Service, MBMS


Multimedia Broadcast Multicast Service, MBMS

A new service introduced in 3GPP Release 6 specifications is Multimedia Broadcast Multicast Service (MBMS). There are two high level modes of operation in MBMS, as given

 

1.       Broadcast mode, which allows sending audio and video. The already existing Cell Broadcast Service (CBS) is intended for messaging only. The broadcast mode is expected to be a service without charging and there are no specific activation requirements for this mode.

2.        Multicast mode allows sending multimedia data for the end users that are part of a multicast subscription group. End users need to monitor service announcements regarding service availability, and then they can join the currently active service. From the network point of view, the same content can be provided in a point-to-point fashion if there are not enough users to justify the high power transmission. A typical example in 3GPP has been the sport results service where, for example, ice hockey results would be available as well as video clips of the key events in different games of the day. Charging is expected to be applied for the multicast mode.

 

From the radio point of view, MBMS is considered an application independent way to deliver the MBMS User Services, which are intended to deliver to multiple users simultaneously. The MBMS User Services can be classified into three groups as follows

1. Streaming services, where a basic example is audio and video stream;

2. File downloads services;

3. Carousel service, which can be considered as a combination of streaming and file download. In this kind of service, an end user may have an application which is provided data repetitively and updates are then broadcast when there are changes in the content.

 

For MBMS User Services, an operator controls the distribution of the data. Unlike CBS, the end user needs first to join the service and only users that have joined the service can see the content. The charging can then be based on the subscription or based on the keys which enable an end user to access the data. The MBMS content can be created by the operator itself or by a third party and, as such, all the details of what an MBMS service should look like will not be specified by 3GPP, but left for operators and service providers. One possible MBMS high level architecture is shown in Figure, where the IP multicast network refers here to any server providing MBMS content over the Internet.
 
 
 
 

 

Push-to-Talk over Cellular (PoC)

Push-to-talk over cellular (PoC) service is instant in the sense that the voice connection is established by simply pushing a single button and the receiving user hears the speech without even having to answer the call. While ordinary voice is bi-directional, the PoC service is a one directional service. The basic PoC application may hence be described as a walkie-talkie application over the packet switched domain of the cellular network. In addition to the basic voice communication functionality, the PoC application provides the end user with complementary features like, for example:

      ·         Ad hoc and predefined communication groups;

·         Access control so that a user may define who is allowed to make calls to him/her;

·         ‘Do-not-disturb’ in case immediate reception of audio is not desirable.

With ordinary voice calls a bi-directional communication channel is reserved between the end users throughout the duration of the call. In PoC, the channel is only set up to transfer a short speech burst from one to possibly multiple users. Once this speech burst has been transferred, the packet switched communication channel can be released. This difference is highlighted in Figure.




 
 
The speech packets are in the PoC solution carried from the sending mobile station to the server by the OPRS/UMTS network. The server then forwards the packets to the receiving mobile stations. In the case of a one-to-many connection, the server multiplies the packets to all the receiving mobile stations. This is illustrated in Figure  The PoC service is independent of the underlying radio access network.

 

 
 


Differences between WCDMA and Second Generation Air Interfaces

Main differences between the third and second generation air interfaces are described. GSM and IS-95 (the standard for cdmaOne systems) are the second generation air interfaces considered here. Other second generation air interfaces are PDC in Japan and US-TDMA mainly in the Americas; these are based on TDMA (time division multiple access) and have more similarities with GSM than with IS-95. The second generation systems were built mainly to provide speech services in macro cells. To understand the background to the differences between second and third generation systems, we need to look at the new requirements of the third generation systems which are listed below:

       ·         Bit rates up to 2 Mbps;

·         Variable bit rate to offer bandwidth on demand;

·         Multiplexing of services with different quality requirements on a single connection, e.g. speech, video and packet data;

·         Delay requirements from delay-sensitive real time traffic to flexible best-effort packet data;

·         Quality requirements from 10 % frame error rate to 10_6 bit error rate;

·         Co-existence of second and third generation systems and inter-system handovers for coverage enhancements and load balancing;

·         Support of asymmetric uplink and downlink traffic, e.g. web browsing causes more loading to downlink than to uplink;

·         High spectrum efficiency;

·         Co-existence of FDD and TDD modes.


GSM also covers services and core network aspects, and this GSM platform will be used together with the WCDMA air interface: see the next section regarding core networks.
 
 
 
 
 
 

What is Bluetooth ?

Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances (using short-wavelength radio transmissions in the ISM band from 2400–2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security. Created by telecoms vendor Ericsson in 1994,[1] it was originally conceived as a wireless alternative to RS-232 data cables. It can connect several devices, overcoming problems of synchronization.
To understand any kind of communication technology, you should be able to answer to several basic questions about it. In other words, if you can answer the following questions, I would say you already have some general understanding on it.

  • Is it wired communication? or Wireless communication ?
  • If it is wireless communication, what kind of wave length (frequency) range it uses ?
  • What is the typical range of communication? (How far it can go) ?
  • What is the typical data rate you can transmit and receive ?
  • What is the typical connection topology ? (Is it one-to-one connection ? or one-to-many connection ? etc)

Can you find the answers to these questions from the wikipedia definition that I quoted above?

Let's tackle each of the questions one by one.
  • Is it wired communication? or Wireless communication ? ==> It is 'wireless Communication'.
  • If it is wireless communication, what kind of wave length (frequency) range it uses? ==> It is 2400~2800 Mhz frequency Range called ISM (Industrial Science Medical) band.
  • What is the typical range of communication ? (How far it can go) ? ==> It is usually a couple meter range (The wikipedia definition does not explictely say about the range though)
  • What is the typical data rate you can transmit and receive ? ==> At the beginning, it started with the max data rate of 1 Mbp and now mostly 2,3 Mbps (EDR). Recent specification defines the technology for even higher data rate.
  • What is the typical connection topology ? (Is it one-to-one connection ? or one-to-many connection ? etc) ==> It support both one-to-one and one-to-many connection.
 Typical Bluetooth Application


Headset
Hands-free Automotive
Dial-up Networking
Ad-hoc File Transfer
PC-Peripherals,
Printing
Stereo Audio
Image
Home Automation
Music Player Synch
Video Transfer
Smart Remotes






Convert Latitude/Longitude to Decimal

Degrees, Minutes, Seconds to/from Decimal Degrees

The form below allows you to convert Latitude and Longitude information between decimal format and degree/minute/second (DMS) format. This is useful when finding distances. Here's the basic equation:
     Decimal Degrees = Degrees + minutes/60 + seconds/3600

Decimal
Lat
Long



Deg Min Sec
Lat
Long

LAPD protocol

All messages sent on the A-bis interface use the LAPD protocol that enables reliable transmission of information. LAPD provides two kinds of transfer modes: Unacknowledged info transfer with no guarantee that the information frame is successfully delivered to the addressee, and acknowledged information transfer, where each signal is acknowledged, and the system makes sure that the frame has reached the destination successfully. Only measurement reports use unacknowledged information transfer.
Frame Structure and Data Links
A flag, 01111110 (h'7E), delimits a frame. The one flag is enough between consecutive frames. The receiving entity looks for the flag 01111110 to synchronize on the start of a frame.

TEI and SAPI are used to access the right entity and right function at the receiving end.
SAPI
is the address used to access different functions, such as TRXC, CF and Layer 2 management procedures, within one physical entity. The CF (Central Function) link is used in RBS 2000 for common management functions for the TG, for example BTS software download.



TEI
is the address used to access different physical entities such as an individual TRX for radio signaling.

Two data link types are defined for each TEI. The data link types and their corresponding SAPI are:
SAPI=0
is used for the Radio Signaling Link (RSL). This link is used for supporting traffic management procedures mainly for circuit switched traffic. Signalling on Packet Data Channels (PDCH) is not carried by the RSL link. One link is required per TRX defined.

SAPI=62
is used for the Operations & Maintenance Link (OML). This link is used for supporting network TRXC management procedures.

The physical entities (TRX) that BSC communicates with at the BTS, via data links, are referred to as Terminal Equipment. A TEI/SAPI pair, unique within each physical connection identifies each data link. Each physical connection can support a number of data links.
Each TRX have one OML and one RSL signaling link. Additionally there is a CF signalling link to the DX function in the RBS2000. These links use the LAPD protocol:
  • The CF link is identified by the TEI value (configurable) and SAPI=62.
  • The OML link is identified by the TEI value for the TRX and SAPI=62.
  • The RSL link is identified by the TEI value for the TRX and SAPI=0.
  • The TRX TEI value is defined by the TRX position in the RBS cabinet.
The LAPD concentrator receives messages from several TRXs and sends these messages on one 64 kbit/s Abis time slot to BSC. The LAPD concentrator also receives messages on this Abis time slot from the BSC and distributes them to the TRXs.
Without LAPD Concentration and LAPD Multiplexing each 64 Kbits/s A-bis time slot can support signalling for only one TRX.
With LAPD Concentration each 64 Kbits/s A-bis time slot can support signalling for up to four TRXs. The allocation of bandwidth between the different TRXs sharing a 64 kbit/s A-bis time slot is dynamic: the concentration is implemented as separately addressed messages which are sent over the common path. This means both transmission delays are minimized - LAPD Concentration is superior to LAPD Multiplexing when it comes to delays and thoughput performance.


GSM PHASES


In the late 1980s, the groups involved in developing the GSM standard realized that within the given time-frame they could not complete the specifications for the entire range of GSM services and features as originally planned. Because of this, it was decided that GSM would be released in phases with phase 1 consisting of a limited set of services and features. Each new phase builds on the services offered by existing phases.


Phase 1
Phase 1 contains the most common services including:
·         Voice telephony
·         International roaming
·         Basic fax/data services (up to 9.6 kbits/s)
·         Call forwarding
·         Call barring
·         Short Message Service (SMS)
Phase 1 also incorporated features such as ciphering and Subscriber Identity Module (SIM) cards. Phase 1 specifications were then closed and cannot be modified.

Phase 2
Additional features were introduced in GSM phase 2 including:
·         Advice of charge
·         Calling line identification
·         Call waiting
·         Call hold
·         Conference calling
·         Closed user groups
·         Additional data communications capabilities

Phase 2+
The standardization groups have already defined the next phase, 2+. This program covers multiple subscriber numbers and a variety of business oriented features. Some of the enhancements offered by Phase 2+ include:

·         Multiple service profiles
·         Private numbering plans
·         Access to Centrex services
·         Interworking with GSM 1800, GSM 1900 and the Digital

Enhanced Cordless Telecommunications (DECT) standard Priorities and time schedules for new features and functions depend primarily on the interest shown by operating companies and manufacturers and technical developments in related areas.

Phase 2++ This phase includes sophisticated enhancements to the radio interface including:

·         Enhanced Datarates for Global Evolution (EDGE), a new modulation method which increases capacity on the air interface.
·         Customized Application for Mobile Enhanced Logic (CAMEL), a standard, governing IN service access while roaming internationally.
·         High Speed Circuit Switched Data (HSCSD), a method of delivering higher data rates per subscriber by allocating an increased number of time-slots per call.

Types of Alarm

TGC FAULT No active TGC application exists in the Transceiver Group.

PERMANENT FAULT A managed object is classified as being permanently faulty when fault situations have occurred, and have been cleared, a certain number of times within a certain period of time. Manual intervention is required to bring such equipment back into operation.

LOCAL MODE The BTS equipment is in Local Mode or the BTS equipment has changed from Local to Remote Mode and a fault exists in the communication link between the BSC and the BTS. Communication between the BSC and the BTS is not possible.

LMT INTERVENTION Local maintenance activities are being performed in the BTS.

LOOP TEST FAILED Test of the traffic carrying capabilities of the TS has failed.

BTS INTERNAL There is a fault internal to the BTS.

MAINS FAILURE There is a fault in the power supply to the BTS or one or more items of equipment within the BTS. Battery backup (where available) is in use. Escalation may occur if corrective action is not  taken.

BTS EXTERNAL There is a fault external to the BTS.

OML FAULT There is a fault in the communications link between the BSC and BTS.

ABIS PATH UNAVAIL No transmission device exists between the BSC and BTS.

CON QUEUE CONGESTION At least one of the LAPD Concentrator concentration outlet queues has reached an unacceptable filling level.

TS SYNC FAULT Synchronization lost on uplink or downlink TRA or PCU channels.

FORLOPP RELEASE A fault has occurred within the BSC software leading to a Forlopp release. Automatic recovery procedures are taking place. Report to your Ericsson Support Office. Alternatively, this alarm is issued as an advisory following a command ordered Forlopp release of a TG. In either case, the alarm is automatically ceased following successful recovery.

OPERATOR CONDITION A condition has arisen due to operator intervention.

How to calculate Peak Data Rate in LTE


The Peak Data rate of LTE is about 400Mbps?   It’s in a simple way to calculate date rate in LTE.

First: Assume That 20 MHz channel bandwidth, normal CP, 64QAM  and  4x4 MIMO technology are used.

Second: Calculate the number of resource elements (RE) in a subframe with 20 MHz channel bandwidth:
12 subcarriers x 7 OFDMA symbols x 100 resource blocks x 2 slots= 16800 REs per subframe. Each RE can carry a modulation symbol.

Third:  Assume 64 QAM modulation and no coding, one modulation symbol will carry 6 bits.
The total bits in a subframe (1ms) over 20 MHz channel is 16800 modulation symbols x 6 bits / modulation symbol = 100800 bits. So the data rate is 100800 bits / 1 ms = 100.8 Mbps.

Fourth:  with 4x4 MIMO, the Peak Data rate goes up to 100.8 Mbps x 4 = 403 Mbps.


EPG on Juniper

          

Based on the Juniper M320 or M120 router, the EPG supports Physical Interface Cards (PICs) of the following types:
·         EPG services PIC: All EPG application software entities run on the EPG services PIC. These entities consist of Globe Session Controller (GSC), SGW Session Controller (SSC) and PGW Session Controller (PSC) for Control Plane, and Packet Processor (PP) and L2TP Packet Processor (TPP) for User Plane. The EPG services PIC is PB-GGSN3 Services PIC.
·         Network interface PIC: The network interface PIC provides 1GE or 10GE Ethernet connectivity for the EPG.
·         Standard services PIC: the standard services PIC runs platform-generic services, such as encapsulation and decapsulation of user payload into Generic Routing Encapsulation (GRE) or IPsec tunnels.
For EPG on Juniper, the following Network Interface PICs are supported:
·         2-Port Gigabit Ethernet  PIC
·         4-Port Gigabit Ethernet PIC
·         8-Port Gigabit Ethernet PIC
·         10-Port Gigabit Ethernet PIC
·         1-Port 10Gigabit Ethernet PIC
Note: The 10-Port Gigabit Ethernet PIC is only used by the EPG on M320 router.
Both M120 and M320 routers contain 4 and 8 Flexible PIC Concentrators (FPCs) respectively, which are used for the PIU container installation. In addition, two compact FPC (cFPC) slots are available on the M120 router for transport purposes only.
A single FPC or a cFPC slot in the EPG on M120 router has a maximum throughput of 10 Gbps full duplex.  A single FPC slot on the M320 router has a maximum throughput of 16 Gbps or 20 Gbps full duplex. 

EPG- Evolved Packet Gateway


The EPG combines the GGSN, SGW and PGW functions in one physical node. In addition, the evolved platform adaptation layer supports the EPG application running on both operating systems: Junos OS (the OS of Juniper M series routers) and IPOS (the OS of Smart Services Router), 
The EPG is available on different hardware platforms:
·         Juniper (M320, M120)
·         Smart Services Router (SSR 8020)


The EPG based on Juniper hardware is simply called EPG on Juniper and the EPG based on SSR hardware is respectively called EPG on SSR. In the EIN documents, these terms are used to distinguish between these hardware platforms. If the hardware platform does not matter, the EPG term covers all possible EPG configurations.
The EPG on SSR has an increased capacity, up to 10 times greater than the EPG on Juniper. Therefore, the EPG on SSR has a big impact on the PS core network, and this needs to be sustained in terms of capacity from the other PS network elements and transmission systems.

The EPG on SSR is not a product designed only for high capacity networks. Its scalable configuration suits it perfectly for small and medium networks with potential for further extensions.
The EPG can be ordered and deployed in the following deployment modes for single and combined functions:
·         GGSN only functionality
·         PGW only functionality
·         SGW only functionality (applicable only to EPG on SSR)
·         Combined SGW and PGW
·         Combined GGSN and SGW and PGW

RAN OSS - Technical Certification

Ericsson - RAN OSS Radio Access Networks - Technical Certification overview
RAN OSS
Knowledge objective, the candidate should be able to identify and describe:
The role of OSS in Ericsson Business Support System, the products, functionalities and features: OSS-RC, ENIQ Event, ENIQ Statistics, SON, ENM, etc. Main advantages/values as well as impact on RAN performance and OPEX reduction.

Importance of OSS
Ericsson Network Manager
Total Network Performance
The Importance of OSS in Self Organizing Networks
Key SON Features for the Mobile Domain
SON Overview
SON detailed functionality
SON based GSM Spectrum Management
OSS Architecture Overview
OSS in Modern Networks  
OSS-RC Overview (WBL)
OSS-RC Applications Overview -
OSS-RC Features and Roadmap (Video)
OSS-RC Functionality for LTE (Centra) 

Ericsson RAN Radio Access Networks - Associate Technical Certification

RAN Fundamentals

Knowledge objective, within this radio technical competence area the candidate should be able to identify and describe the followings:
- The general RAN architecture: Nodes, UE categories, RAN standards, etc.
- Radio design principles: Dimensioning, link budget for radio coverage, multipath propagation, path loss predictions, propagation models and tuning, traffic models, etc
- Air interface principles: Radio channel concept, modulations, spectral efficiency, FDD / TDD, transmission and reception, multiplex access technique principles, mobile technology differences, frequency, voice coding, basic antenna system, dB, dBm, dBi, etc.
- Signaling, protocols and layers: Radio messages, layers, interaction, basic protocols, etc.
- Radio network basic functionalities: mobility, idle mode, call set-up, radio resource mgmt, etc.
- RAN performance: Accessibility, retain ability, integrity, latency and throughput, counter & KPI’s, energy consumption reduction, impact of quality of service, etc.
- RAN lifecycle stages (design, optimization, integration and installation, etc)

     Access Networks an Overview 
     Networking Basics, an Overview 
     Ethernet Standards 
     LTE Fundamentals 
     LTE Radio Interface
     LTE KPIs and Acceptance 
     LTE Network Design Overview 
     LTE Protocols and Procedures 
     LTE Air interface 

LTE  RAN 
Knowledge objective, the candidate should be able to identify and describe:
The fundamental technology and characteristics of LTE RAN, the products & solutions, functionalities and features. Channel structure, bearer concept, network architecture and interfaces, radio planning principles (capacity, limitations, connected users), radio units and their functionality, SW features such as: LTE advanced, voice in LTE, IRAT mobility, QoS handling, etc. LTE introduction in legacy networks FDD vs. TDD. Main advantages/values, as well as impacts on RAN performance.

         LTE Fundamentals 
         LTE/SAE in a Nutshell
         LTE /SAE System Overview
         LTE/EPC Overview 
         LTE Features and Functionality 
          LTE Air Interface 
          LTE Product Strategy 
          Ericsson´s LTE Performance Advantage
          Coverage and Capacity in LTE 
         LTE Shared Network Solutions incl Transport options 
         LTE Multi-Layer Antenna Solutions & Capacity
          LTE RAN Voice Evolution
          LTE Load and Capacity Evolution

WCDMA RAN

Knowledge objective, the candidate should be able to identify and describe:
The fundamental technology and characteristics of WCDMA RAN, the products & solution, functionalities and features. Channel structure, bearer principles, network architecture and interfaces, planning principles (capacity, limitations, interference reduction, robustness, spectrum load), radio units and their functionality, SW features such as: HSPA/MBB functionality, QoS, Smartphone related functionality, and  mobility, etc. Main advantages/values, as well as impacts on RAN performance.
WCDMA Release Overviews 
Mobile Broadband - Enhanced Uplink Evolution 
Secure Smartphone Business 
HSPA Smartphone Capacity Evolution 
High Capacity WCDMA - Flow of users 
Ensuring high performance in high loaded HSPA NW 
Introduction to Service Differentiation and end-to-end QoS 
Uplink Features (

GSM RAN
Knowledge objective, the candidate should be able to identify and describe:
The fundamental technology and characteristics of GSM RAN, the products & solutions, functionalities and features. Channel structure, network architecture and interfaces, planning principles (capacity, limitations, interference reduction, robustness, spectrum load), signal measurements, radio units and their functionality, SW features such as: packet data support, EDGE, VAMOS, HD Voice, etc. Main advantages/values, as well as impacts on RAN performance.

GSM State of the Business 
Thin Layer GSM 
GSM RAN Key Business Areas – Introduction 
GSM KBA – Drive Cost Efficiency 
GSM KBA –  Increase Coverage and Capacity 
GSM KBA – Increase smart device Business, 
GSM Radio Access Network Overview 
GSM / WCDMA Basics 
GSM System Survey 
Monetize on Voice Efficiency: VAMOS 
GSM RAN SW Licensing 
GSM RAN BSC HW Activation Codes 
SON Based GSM Spectrum Management 
Energy Efficiency Features in GSM RAN 
RAN Modernization