Friday, December 14, 2012

HSDPA Frame Loss

These counters relating to frame loss are available on the RBS to monitor HighSpeed data service in the downlink direction.

IubDataStreams::pmHsDataFramesLostSpiXX
- the number of HSdata frames lost, destroyed and errored over Iub in the RBS. There areseparate counters for each of the priority classes.

IubDataStreams::pmHsDataFramesReceivedSpiXX
- the totalnumber of HS data frames correctly received over Iub in the RBS. Thereare separate counters for each of the priority classes.

The XX suffix represents the priority class and can range from 00 to 15.The counters can be used to indicate data loss rate for the HS service.High frame loss will indicate potential congestion problems. RecommendedPerformance Indicator for this is:


Frame Loss Rate on the path from SRNC to RBS

Find more HSDPA Counters at www.telecomfunda.com/forum

Friday, November 9, 2012

VoLTE + Wi-Fi = LTE Femto

This week, Kineto announced it now supports the GSMA’s VoLTE profile (IMS voice & SMS) in its Smart Wi-Fi client. Smartphones with the Smart Wi-Fi client will now be able to receive the mobile operator’s voice/SMS service (VoLTE) when attached to Wi-Fi.
I have always believed LTE and Wi-Fi were two sides of the same coin – both are high-speed, low-latency flat IP networks. LTE covers the macro/outdoor world, and Wi-Fi is by far the dominant in-building wireless technology. Marrying the two technologies into a seamless experience delivers a compelling experience for mobile subscribers.
In the move to LTE, mobile operators are adopting VoLTE, an IMS/SIP-based voice and SMS profile that replaces (replicates?) the existing circuit voice/SMS services used in GSM/UMTS networks.

Thursday, July 26, 2012

UE Measurements

Intra-frequency measurements: measurements on downlink physical channels at the same frequency as the active set. A measurement object corresponds to one cell.
Inter-frequency measurements: measurements on downlink physical channels at frequencies that differ from the frequency of the active set. A measurement object corresponds to one cell.
Inter-RAT measurements: measurements on downlink physical channels belonging to another radio access technology than UTRAN, e.g. GSM. A measurement object corresponds to one cell.
Traffic volume measurements: measurements on uplink traffic volume. A measurement object corresponds to one cell.
Quality measurements: Measurements of downlink quality parameters, e.g. downlink transport block error rate. A measurement object corresponds to one transport channel in case of BLER. A measurement object corresponds to one timeslot in case of SIR (TDD only).
UE-internal measurements: Measurements of UE transmission power and UE received signal level.
UE positioning measurements: Measurements of UE position.The UE supports a number of measurements running in parallel. The UE also supports that each measurement is controlled and reported independently of every other measurement.

Wednesday, July 25, 2012

Cyclic Delay Diversity

Cyclic Delay Diversity (CDD) is a simple approach to introduce spatial diversity to an Orthogonal Frequency Division Multiplexing (OFDM) based transmission scheme that itself has no built-in diversity. It also can be regarded as a Space-Time Code (STC).
But in contrast to that there is no additional effort in the receiver necessary, since the different codewords result in a changed channel impulse response in the receiver. They insert virtual echos and thus increase the frequency selectivity of the channel seen by the receiver. Cyclic Delay Diversity (CDD) is a diversity scheme used in OFDM-based telecommunication systems, transforming spatial diversity into frequency diversity avoiding intersymbol interference.

Tuesday, July 24, 2012

RSRP and RSRQ


In cellular networks, when a mobile moves from cell to cell and performs cell selection/reselection and handover, it has to measure the signal strength/quality of the neighbor cells. In LTE network, a UE measures two parameters on reference signal: RSRP (Reference Signal Received Power) and RSRQ (Reference Signal Received Quality).

RSRP is a RSSI type of measurement. It measures the average received power over the resource elements that carry cell-specific reference signals within certain frequency bandwidth. RSRP is applicable in both RRC_idle and RRC_connected modes, while RSRQ is only applicable in RRC_connected mode. In the procedure of cell selection and cell reselection in idle mode, RSRP is used.

RSRQ is a C/I type of measurement and it indicates the quality of the received reference signal. It is defined as (N*RSRP)/(E-UTRA Carrier RSSI), where N makes sure the nominator and denominator are measured over the same frequency bandwidth.

The carrier RSSI (Receive Strength Signal Indicator) measures the average total received power observed only in OFDM symbols containing reference symbols for antenna port 0 (i.e., OFDM symbol 0 & 4 in a slot) in the measurement bandwidth over N resource blocks. The total received power of the carrier RSSI includes the power from co-channel serving & non-serving cells, adjacent channel interference, thermal noise, etc.

The RSRQ measurement provides additional information when RSRP is not sufficient to make a reliable handover or cell reselection decision. In the procedure of handover, the LTE specification provides the flexibility of using RSRP, RSRQ, or both.

Thursday, July 12, 2012

Benefits of CPICH Optimization

Benefits of CPICH Optimization
  • Improving current 3G coverage and increase 3G traffic
  • Improve in-building penetration for 3G
  • Reduce IRAT HO to 2G
  • Offload traffic from 2G layer

Tuesday, July 10, 2012

What is Pilot Polution?

In idle or cell_FACH mode, phenomenon of the pilot pollution is that a UE cannot firmly camp on a cell at one location because of receiving many pilot channels with similar quality (or signal strength), i.e., Ec/No (or RSCP).
The condition to determine the area has pilot pollution in idle or cell_FACH mode is that third pilot appears in the cell re-selection region.
In cell_DCH mode, phenomenon of the pilot pollution is that a UE at one location frequently changes its active set cells (active set update rate is very high) because of receiving many pilot channels with similar quality (or signal strength), i.e., Ec/No (or RSCP). It causes high signaling load in RRC and Iub interfaces and the capacity of RNC is consequently reduced.
Solution for Pilot Polution in the network:
Reason – no dominant cell
The reason is too many overlapping cells at an area due to poor cell planning.
Solution 1
The direct solution is to remove the cells overlapping by changing the antenna configurations or reducing pilot powers of the unwanted cells.
Solution 2
The most effective solution is to increase the pilot channel power Primary CPICH power of the desired cell.
Solution 3
For the pilot pollution in idle or cell_FACH mode, Q Offset 2sn (CPICH Ec/No) parameter of the desired cell can be increased to create a dominated cell.

Sunday, July 8, 2012

Pilot Channel failure - High Downlink Interference

Symptoms:

From the drive test, following symptoms will be observed by using TEMS:
• Received Ec/No of the pilot channel is less than –16dB and
• Received RSCP of the pilot channel is high enough to maintain the connection,e.g. >-   100dBm and
• DL RSSI is very high and
• The connection finally drops.

Good Excel Sheet on CPICH Calculator

Wednesday, July 4, 2012

What are the functionality of eNodeB?

E-UTRAN consists solely of the evolved Node B (eNB), which is responsible for all radio interface functionality.
eNB is the RAN node in the EPS architecture that is responsible for radio transmission to and reception from UEs in one or more cells.
The eNB is connected to EPC nodes by means of an S1 interface.The eNB is also connected to its neighbor eNBs by means of the
X2 interface. Some significant changes have been made to the eNB functional allocation compared to UTRAN. Most Rel-6 RNC
functionality has been moved to the E-UTRAN eNB. Below follows a description of the functionality provided by eNB.

Good PDF Document on LTE Functionality

Saturday, June 16, 2012

How to get HSDPA users in Ericsson System?

This is the formula:

HSDPA users average cell:

HS_Users = (pmSumBestPsHsAdchRabEstablish) / (pmSamplesBestPsHsAdchRabEstablish)

Click on counter to view detail description in counter.

If you know another way than please share it.

Know more on HSDPA Low Throughput Analysis

Thursday, June 14, 2012

How can I find RRU Type in Ericsson NodeB?

There are several ways to Find RRU type in Node B.

For Ericsson System connect through MOSHELL and

Enter command cabx you can find the RRU type.

Also enter INVH Command for RRU and DUW type.

If You Know More Ways to Know than Discuss Here

Tuesday, May 29, 2012

UMTS/HSPA to LTE Migration

UMTS/HSPA to LTE Migration- A white Paper from Motorola Maximize the life and value of existing assets while achieving a true 4G network

Download Full lenth Paper from Here

Contents
Abstract
- A Dynamic Industry and Technology Evolution
- LTE Performance
- UMTS " LTE Network Architecture Evolution
- Determine the Business Case for LTE
- Subscriber Device Availability
- Deployment Considerations
- Seamlessly Connected Network
- Spectrum Implications
- Maximize Existing Assets
- UMTS to LTE Upgrade Strategy
- UMTS/LTE Architecture
- Functional Elements
- UMTS / HSPA RAN Site Upgrade to LTE
- Backhaul Site Upgrade to LTE
- LTE Voice
- LTE Video

Download Full lenth Paper from Here

Monday, May 28, 2012

Thursday, May 3, 2012

RRC Establishment Causes

RRC Establishment Cause Description
Cause 0 Originating Conversational Call
Cause 1 Originating Streaming Call
Cause 2 Originating Interactive Call
Cause 3 Originating Background Call
Cause 4 Originating Subscribed traffic Call
Cause 5 Terminating Conversational Call
Cause 6 Terminating Streaming Call
Cause 7 Terminating Interactive Call
Cause 8 Terminating Background Call
Cause 9 Emergency Call
Cause 10 Inter-RAT Cell re-selection
Cause 11 Inter-RAT Cell change order
Cause 12 Registration
Cause 13 Detach
Cause 14 Originating High Priority Signaling
Cause 15 Originating Low Priority Signaling
Cause 16 Call re-establishment
Cause 17 Terminating High Priority Signaling
Cause 18 Terminating Low Priority Signaling
Cause 19 Terminating – cause unknown


 

Sunday, April 8, 2012

What are Events that can trigger the HSDPA Cell Change?

Event 1d HS – Change of Best Cell in the Active Set
Event 1b or Event 1c – Removal of the Best Cell from the Active Set



Saturday, April 7, 2012

What will be the impact when you change ‘reportingrange1a’ from 3 to 4 dB and ‘timetotrigger1a’ 100 to 320 ms, without changing any other parameters?

  • Reduction in number of Event1a
  • Delayed Event1a trigger
  • Reduction in Average Active Set Size
  • Delay in Event1a could increase DL interference, which could lead to a drop call or increase in Average Power Per User (reduction in cell capacity)

Thursday, April 5, 2012

What are the possible causes for an Access Failure in UMTS?

  • Missing Neighbors
  • Poor Coverage
  • Pilot Pollution / Spillover
  • Poor Cell Reselection
  • Core Network Issues
  • Non – availability of resources. Admission Control denies
  • Hardware Issues
  • Improper RACH Parameters
  • External Interference
LTE The Vision Beyond 3G by Nortel
Ericsson Parameters to make Handover Easier

Wednesday, April 4, 2012

What is Soft Handover Overhead? What is the typical value in UMTS network?

  • Soft Handover Overhead is calculated in two ways. 1) Average Active Set Size – Total Traffic / Primary Traffic. 2) Secondary / Total Traffic
  • Typical Values are like 1.7 (Avg Active Set Size) or 35% (Secondary / Total )
How to improve Soft Handover in UMTS Network?
How can we avoide to many Soft Handover attempts?

Tuesday, April 3, 2012

What is the typical Call Setup Time for a 3G UE to 3G UE Call? What are the possible RF related causes for a delayed CST in this type of call?

  • 6 to 9 seconds
  • Multiple RRC Attempts (UE is on poor coverage – need more than Access Attempt)
  • Delayed Page Responses
  • High Load on Paging and/or Access Channel
  • Paging / Access Parameters
Download UMTS Radio System Planning and Optimization Guide

Sunday, April 1, 2012

What can we try to improve when access failure is high?

When access failure is high we can try the following to improve RACH performance:
  • Increase maximum UE transmit power allowed: Max_allowed_UL_TX_Power.
  • Increase power quickly: power_Offset_P0.
  • Increase number of preambles sent in a given preamble cycle: preamble_Retrans_Max.
  • Increase the number of preamble cycles: max_Preamble_Cycle.
  • Increase number of RRC Connection Request retries: N300.
Know What are the Possible Reasons for Access Failure in UMTS?

What is Hard Handover in UMTS? When will it happen?

· Hard Handover in UMTS is a break before make type Handover
· It can happen in the inter RNC boundaries where there is no Iur link.

This may Helpful to You

IRAT Handover Guide
Inter System Cell Reselection Optimization Guide
TEMS UMTS Dropped and Block Call Specification 

Sunday, March 18, 2012

What are the possible causes for a Drop Call on a UMTS network?

There are several reasons for RAB Drop in WCDMA network.

·         Poor Coverage (DL / UL)
·         Pilot Pollution / Pilot Spillover
·         Missing Neighbor
·         SC Collisions
·         Delayed Handovers
·         No resource availability (Congestion) for Hand in
·         Loss of Synchronization
·         Fast Fading
·         Delayed IRAT Triggers
·         Hardware Issues
·         External Interference

You may like this
WCDMA Optimization Tech for Drive Test
WCDMA Neighbor Cell, Scrambling Code and LAC Planning
TEMS UMTS Dropped & Blocked Call Specifications

Friday, March 16, 2012

What are the possible causes for a lower PSR?

There are several different reason for low Paging Success Ratio

- Non-continuous RF Coverage – UE going in and out of coverage area frequently
- Very High ‘Periodic Location Update Timer’ – Keeping UEs in VLR long time after it moved out of coverage
- Lower Paging Channel Power
- Access Channel Parameter Issues
- Delayed Location Update when crossing the LA / CN Boundaries

Also Check

Monday, February 27, 2012

How WCDMA OSS Works?

Doc For This with Below Containing :
  • Cell & Channel Management
  • Adjacent Cell Configuration Management
  • Radio Network Optimization
  • WCDMA Neighboring Cell Support (WNCS)
  • WCDMA Measurement Result Recording (WMRR)
  • Alarms Status Matrix
  • Alarm Log Browser
  • Alarm List Viewer
  • Element Manager
  • RNC Element Manager
  • RBS Element Manager
  • Bulk Configuration C
Doc Link : WCDMA OSS DOC

Tuesday, February 21, 2012

What is Paging Success Ratio? What is the typical PSR that you have seen in a WCDMA UMTS network?


Paging Success Ratio:

Its Paging Responces to the Paging Attempts in WCDMA UMTS network.

Typical Value for Good WCDMA Cellular Network is greater than 90%. 

Monday, February 20, 2012

What are the possible causes for an IRAT Failure?


There are several reasons for IRAT failure in cellular network optimization.
Major 4 reasons which played good role in WCDMA Optimization.

·         Missing 2G relations
·         Non availability of 2G Resources
·         Poor 2G Coverage
·         Missing 3G Relations