Telecom 4G and LTE Posters

Please Click on the links below to view/Download the Posters .

Telecom Networks Posters by Nexus : Click Here

LTE Evolved Packet System Architecture by Alcatel Lucent  : Click Here

Next Generation Mobile Network – The Evolution to 4G : Click Here

LTE-Advanced by  Rohde-schwarz : Click Here

WIMAX poster by Aniritsu : Click Here

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KPIs for LTE

Lits of KPI's for LTE optimization.

These are  just a list of KPI's for LTE optimization, Please let us know if you know more so we can update it here.

• eRAB Establishment Success Rate (%) 
• Abnormal eRAB Release (%) 
• Total number of eRABs (per cell) 
• RRC establishment Success Rate (%) 
• Intra LTE mobility Success Rate (%) 
• Connected Users License capacity limit (per RBS) 
• Average percentile of Connected Users License utilization (per RBS) 
• Connected Users License (CUL) Time Congestion (per cell) 
• RRC Failure Rate due to CUL (per cell) 
• Peak number of Connected Users (per cell) 
• DL Baseband Capacity utilization per RBS (%) 
• UL Baseband Capacity utilization per RBS (%) 
• Average DUL main Processor Load (%) 
• Peak number of UE in RRC_CONNECTED mode 
• Number of neighbour relations added by the ANR function 
• Number of neighbour relations removed by the ANR function 
• PDCCH utilization per cell (%) 
• Average UE DL Throughput (Mbps) 
• Average UE UL Throughput (Mbps) 
• DL PDCP volume per cell (kilobits) 
• UL PDCP volume per cell (kilobits) 
• Average cell throughput (PDCP DRB) DL (kbps) 
• Average cell throughput (PDCP DRB) UL (kbps) 
• Max UE DL Latency (ms) 
• Physical Resource Block (PRB) 
• DL Physical Resource Block (PRB) utilization (per cell) 
• UL Physical Resource Block (PRB) utilization (per cell) 
• Average Noise and Interference Power on PUSCH 
• Average Noise and Interference Power on PUCCH

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LTE Initial Attach Call Flow ( Part 1 )

In this case we will look initial attach procedure of an unknown UE to a LTE network for the first time.

1)  Radio Link synchronization:
In order for the UE to connect to eNB it needs to establish a radio connection with eNB. UE selects the eNB through PLMN selection and cell search procedure. After an RRC signalling connection the UE can then communicate with the eNB. UE is in EMM-De-registered state at this point of time.

2) ECM connection establishment:
UE sends an attach Request (IMSI, UE capability) message to MME via eNB through NAS layer.In order for the attach request message to  be delivered to MME, ECM connection between UE and MME is required.At the end of ECM connection, RRC connection between UE and eNB  and S1 signalling  connection between eNB and MME is required.NAS messages are send as RRC messages when passing through RRC connection and SI AP when passing through S1 signalling collection.

3) RRC Connection Establishment:
An RRC connection is established between the RRC layers of UE and eNB.
The procedure of RRC connection between UE and eNB is as follows.

UE--->eNB [ RRC connection request ]
UE sends an 'RRC connection request' to eNB  ( Establishment Cause=“Mobile Originating Signalling”). The message sent by UE is  delivered to eNB through SRB 0 and  CCCH ( Common control channel )
SRB 0 is used by all UE's in a cell.

eNB --> UE [ RCC connection setup ]
The eNB allocates SRB1 to UE by sending an RRC connection setup message, which is delivered through SRB 0 and CCCH.Now the uplink/downlink resources of the UE are controlled by eNB.UE can now use the resources allocated to UE by eNB through SRB configuration.

UE --> eNB [ RRC Connection Setup Complete ]
The UE notifies the eNB that the RRC connection setup is completed by sending it an RRC Connection Setup Complete message through SRB 1 and DCCH (Dedicated Control Channel).The attach request message that was delivered to the NAS layer is sent to eNB along with RRC connection setup complete message.


4) S1 Signalling connection establishment:

Control messages between eNB and MME are sent Over S1-MME interface as embedded in S1 AP messages. S1-AP messages are delivered through S1 signalling connections dedicatedly for each user.S1 Signalling connections are defined by an ID pair ( eNB UE  S1 AP ID , MME UE S1 AP ID). These are allocated by eNB and MME for identifying UE's .The eNB allocates an eNB UE S1 AP ID for establishment of S1 signalling connection and sends the MME an attach request as embedded in  an ' initial UE message'. The Attach Request message is delivered as embedded in the NAS-PDU field of the Initial UE Message. The Initial UE Message consists of the following information elements:
Initial UE Message (eNB UE S1AP ID, NAS-PDU, TAI, ECGI, RRC Establishment Cause) 

• eNB UE S1AP ID: ID identifying UEs in an eNB over S1-MME interface (Uplink) 
• NAS-PDU: a NAS message (Attach Request) 
• TAI: shows the TA a UE is located in 
• ECGI: shows the cell a UE is located in 
• RRC Establishment Cause = mo-Signalling: indicates the signalling was generated by a UE

Now MME received the UE intial context message and assigns an  MME SI AP UE ID. After the allocation the signalling connection between the eNB and MME is established. MME S1 AP UE ID is used later when MME identifies UE over S1-MME interface.

5) IMSI Acquisition 
The NAS layer of the MME acquires the IMSI of  the UE from the intial message and also determines the network capability of the UE and the security algorithms it supports.Now the MME performs authentication and NAS security keys setup procedures for secured delivery of NAS messages.

An Overview Till Now :

• UE Has sent an RRC connection request.
• eNB Receives RRC connection request and sends UE RRC connection setup message and allocates resources to UE
• UE sends an 'Attach Request' along with RRC connection complete message to eNB 
• eNB initiates S1 Signalling connection  between eNB and MME for the UE 
• MME recives Attach request from UE
• MME knows UE IMSI and network capability.

The next will be Available here soon

Please Refer to the List of other topics in LTE tutorials

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LTE Attach in Bullet Points

UE switched ON - Cell selection

UE > eNB - RRC connection request

eNB > UE - RRC connection set-up

UE > eNB - RRC Connection complete+ Attach request + PDN conn request

eNB > MME - Initial UE message + NAS-PDU ( Attach request + PDN conn request )

MME > HSS - Authentication request ( Acquisition of Authentication vector )

HSS > MME - Authentication information Answer ( RAND, AUTN, XRES, Kasme )

MME > UE -  Authentication request ( RAND, AUTN )

UE - UE generates Auth response from the information received and uses the same algorithm HSS used to generate AV

UE > MME - Authentication response ( RES )

MME - Authenticates UE if RES = XRES (  UE authenticated )

MME - Generates Security keys 

MME > UE -  Security Mode  command

UE - Generates NAS keys

UE > MME - Security mode Complete. 

MME > HSS - Location update request

HSS - Registers UE IMSI , MME ID.

HSS > MME -  Update location answer  ( Subscriber profile + APN + P-GW + QoS )

MME - MME stores APN & subscriber profile 

MME - Assigns EPS bearer ID & P-GW selection by HSS or MME

MME > S-GW - Create session request 

S-GW > P-GW - Create session request

P-GW - Assigns IP address to UE 

P-GW > PCRF -  Notification of EPS session set-up

PCRF - Determines PCC ( Policy charging & control ) policies for the EPS session to established

PCRF > P-GW - Acknowledging EPS Session Establishment

P-GW - Policy Enforcement (Install Policy Rule)

P-GW > S-GW - Create session response

S-GW > MME - Create session Response

MME - Generates Various parameters ( UE AMBR  )

MME - eNB - Initial context set-up request ( Attach accept in NAS-PDU )

eNB - Receives S-GW address and generates keys 

eNB > UE -  Security mode command

UE - UE generates Kenb and AS keys

UE > eNB - Security mode complete

eNB > UE - RRC connection reconfiguration + Attach Accept

UE - DRB is created between UE and eNB

UE > MME - Attach complete ( via eNB )

eNB > MME - Initial context set-up response

MME > S-GW -  - Modify bearer request + eNB address + EPS bearer ID

S-GW > MME -  Modify bearer response

S1 bearer is established between eNB and S-GW. EPS default bearer is UP and user can exchange data.

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Why is LTE important

Long Term Evolution (LTE) is important because it will bring up to a 50x performance improvement and much betterspectral efficiency to cellular networks. LTE is different from other technologies that call themselves 4G because it is completely integrated into the existing cellular infrastructure for 2G and 3G.

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LTE- UPLINK Physical layer Singnalling.

Up link L1/L2 control signalling is divided into two classes in the LTE system

1. Control signalling in absence of up-link data , which is done by PUCCH ( Physical up-link control channel) i.e when the UE is in IDLE Mode and has no dedicated resources allocated to it, only then the control signalling is carried on PUCCH.

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System Information Blocks and their contents

SIB 1: Cell access related parameters and scheduling

SIB 2: Common and shared channel configuration

SIB 3: Parameters required for intra-frequency cell reselections

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enodeB functions

enodeB is responsible for radio transmission between UE and enodeB

Functionality of eNodeB

• Radio resource Management(RRM) in general
• Admission control
• Radio bearer control

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LTE Basics - Document

A white Paper on Long Term Evolution Protocol Overview

Contents of This white paper

• LTE Architecture
• 
  
• Life of an LTE Packet - Uplink - Downlink
• 
  
• Diffrent LTE Layers and their operation

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What is the Difference between 4G and 4G LTE

Current LTE and WiMAX implementations are often cited in the marketplace as 4G, although they don't fully comply with the planned requirements of 1 Gbps for stationary reception and 100 Mbps for mobile. The common argument for branding LTE and WiMAX systems as 4G is that they use different frequency bands to 3G technologies; that they are based on a new radio-interface paradigm; and that the standards are not backwards compatible with 3G, while some of the standards are expected to be forwards compatible with "real" 4G technologies.  

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What is 3G and 4G

Often there is a Misunderstanding between different generations of technologies and their technical names , Here is the List of the Generations of technology .

2G = GSM

2.5G = GPRS

2.75G = EDGE

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4G LTE Basics

4G (LTE) Basics

•LTE stands for Long Term Evolution

•Next Generation mobile broadband technology

•Promises data transfer rates of 100 Mbps

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