RF Optimization

What is LIPA?

2013-08-08T21:37:00.000+05:30

Local IP Access (LIPA) is the ability for an IP-enabled device to access a consumer’s home-based local area network as well as the broader Internet directly using the air interface of a femtocell, or Home NodeB (HNB). Using LIPA allows for greater performance, innovative services that mesh mobile and home networks, and the off-loading of traffic from the operator’s packet core network which is ultimately destined for the Internet.

Why LIPA?
As connected device (i.e., mobiles, laptop data cards, USB dongles, etc.) penetration increases globally, more and more users are using their mobile devices not just for voice but also for data services. Today’s high-speed mobile broadband access technologies—

including Wideband CDMA (WCDMA) and Long Term Evolution (LTE)—are ensuring that users have the dual benefits of high mobility and high speed data access. The ever-increasing content available online via email, social networking sites, blogs, RSS feeds, multimedia calls, streaming video and online music coupled with faster and higher capacity equipment driven by personal digital assistants (PDAs), smartphones and netbooks have led to a boom in the demand for Internet data access using high-speed mobile network infrastructure.

Requirements Related to LIPA

The requirements for Local IP Access can be broadly classified into two main categories: LIPA to the home network and IP access to the Internet. For LIPA to the home network, the User Equipment (UE) should be able to exchange data via the operator’s core network and LIPA to the home-based network simultaneously, depending upon the destination.
The HNB should decide, based upon policies, whether to route the data via the core network or to use LIPA.
Furthermore, the UE should be able to access other devices on the home network via the HNB using the HNB only as an access medium.

What is IU Paging Success Ratio?

2013-07-25T22:51:00.000+05:30

IU Paging Success Ratio defied for Huawei system.

This KPI can be used to evaluate the successful paging responses to the pagings from the Core Network (CN) in one RNC.

The Attempt Paging Procedure starts when the CN sends a PAGING message to the RNC, and finishes when the UE in idle mode receives the PAGING TYPE 1 message from the RNC.

The Successful Paging Procedure finishes when the RNC receives an RRC CONNECTION REQUEST from the UE in idle mode.

IU Paging Success Ratio =
(VS.RANAP.Paging.Succ.IdleUE/ VS.RANAP.Paging.Att.IdleUE)*100%

QoS Class Identifier (QCI)

2013-04-15T00:11:00.000+05:30

The need for supporting a broader variety of applications requiring higher bandwidth and lower latency led 3GPP to alleviate the existing QoS principles with the introduction for EPS of a QoS Class Identifier (QCI).
LTE provides different QoS for a given application by putting it into the different bearer . each bearer has its own QCI (QoS Class Identifier) which introduce a particular service for a particular application. as far as I know 9 different QCIs have been defined in LTE based on priority,packet loss and delay.

Download more on LTE Basics and LTE Optimization

The QoS architecture in EPC enables a number of important capabilities for both operators and users:

VoIP support with IMS: QoS is a crucial element for providing LTE/IMS voice service.
Enhanced application performance:Applications such as gaming or video can operate more reliably.
More flexible business models:With flexible, policy-based charging control, operators and third-parties will be able to offer content in creative new ways. For example, an enhanced video stream to a user could be paid for by an advertiser.
Congestion control: In congestion situations, certain traffic flows (e.g., bulk transfers, abusive users) can be throttled down to provide a better user experience for others.

Congestion Indicators for EUL

2013-04-14T00:04:00.000+05:30

Congestion Indicators for EUL

Iub overload problems are solved by flow control for Enhanced Uplink highspeed data services. For EUL increased delay is measured internally and thedata flow from RBS in UL is throttled according to measurements recorded,therefore there is no congestion as such but rather the transmission rate of thedata is slowed down in the uplink direction when potential overload is detected.There are counters which can be used to monitor when the Iub tends towardscongestion for EUL services. When that happens it should be considered toexpand the Iub capacity for EUL services.

Click Here to get more info on How to Know HSDPA Frame Loss?

Iub Limiting EUL Performance
EUL Frame Loss
EUL Dynamic Delay of Frames

HSDPA Frame Loss

2012-12-14T23:30:00.000+05:30

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

VoLTE + Wi-Fi = LTE Femto

2012-11-09T07:21:00.001+05:30

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.
As mobile voice/SMS account for well over 50% of mobile operator revenues, ensuring these capabilities are available on LTE is critical. So extending VoLTE to Wi-Fi just makes sense.
A smartphone at home (or in the office) will want the same high speed experience as the outdoor LTE network, and Wi-Fi, already deployed in >400m indoor locations around the world, is ready to deliver.
This got me thinking: What, if any, is the role of an LTE femtocell?
Femtocells, mini base stations designed for home use, have turned on hard times lately. Yet there is some talk of resurgence as the industry moves to LTE – the logic being that LTE networks will be patchy for the time being, and an LTE femto to boost in-home coverage will help accelerate adoption.
But let’s consider the role of a 3G femtocell today, and see if it applies to an LTE deployment/subscriber. A 3G femtocell provides a strong 3G signal in the home, boosting coverage. But really this amounts to a subscriber having access services that reside in the mobile core network – namely voice & SMS.

Sure there may be mobile data services like MMS, Mobile TV, or Visual Voicemail too, but the bulk of the interest, and revenues, are associated with voice/SMS.
In the move to LTE, subscribers will still want to make a phone call, so access to voice/SMS is critical. With Kineto’s Smart Wi-Fi client, smartphones can access VoLTE over Wi-Fi directly, no LTE femtocell needed.

UE Measurements

2012-07-26T21:50:00.000+05:30

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.

Cyclic Delay Diversity

2012-07-25T21:35:00.000+05:30

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.

RSRP and RSRQ

2012-07-24T21:33:00.002+05:30

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.

Benefits of CPICH Optimization

2012-07-12T17:44:00.000+05:30

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

What is Pilot Polution?

2012-07-10T17:36:00.000+05:30

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.

May be useful to you
WCDMA Tilt and CPICH Power Adjustment

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.

Pilot Channel failure - High Downlink Interference

2012-07-08T17:24:00.000+05:30

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

Reason 1 – no dominant cell
Solution:The most direct and effective way to solve this problem is to increase the pilot channel power Primary CPICH power of the desired cell.
Reason 2 – dominant interferer
Solution:The simplest solution to overcome this problem is to include the overshooting cell into the neighboring cell list. This means the interferer now becomes a useful radio link.
Reason 3 – low best serving PPilot/PTot
Solution:The received Ec/No of the best serving pilot channel is very low (near or less than –16dB) even though there is no other cell. It means the pilot power setting is not large enough to fulfill existing downlink load.
Solution 1
The best solution is to add a new site with “good coverage control” at the problematic area.
Solution 2
The direct but ineffective solution is to increase the pilot channel power Primary CPICH power of the problematic cell. With high pilot power, the common channel powers and the required power for the downlink DPCHs will be increased. At the end, the ratio of the PPilot/PTot does not increase much.

What are the functionality of eNodeB?

2012-07-04T21:11:00.000+05:30

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

1. Cell control and MME pool support

eNB owns and controls the radio resources of its own cells.Cell resources are requested by and granted to MMEs in an ordered fashion. This arrangement supports the MME pooling concept. S-GW pooling is managed by the MMEs and is not really seen in the eNB.

2. Mobility control

The eNB is responsible for controlling the mobility for terminals in active state. This is done by ordering the UE to perform measurement and then performing handover when necessary.

Find more on WCDMA Radio Resource Management

3. Control and User Plane security

The ciphering of user plane data over the radio interface is terminated in the eNB. Also the ciphering and integrity protection of RRC signaling is terminated in the eNB.

4. Shared Channel handling

Since the eNB owns the cell resources, the eNB also handles the shared and random access channels used for signaling and initial access.

5. Segmentation/Concatenation

Radio Link Control (RLC) Service Data Units (SDUs) received from the Packet Data Convergence Protocol (PDCP) layer consist of whole IP packets and may be larger than the transport block size provided by the physical layer. Thus, the RLC layer must support segmentation and concatenation to adapt the payload to the transport block size.

6. HARQA Medium Access Control (MAC) Hybrid Automatic Repeat reQuest (HARQ) layer with fast feedback provides a means for quickly correcting most errors from the radio channel. To achieve low delay and efficient use of radio resources, the HARQ operates with a native error rate which is sufficient only for services with moderate error rate requirements such as for instance VoIP. Lower error rates are achieved by letting an outer Automatic Repeat reQuest (ARQ) layer in the eNB handle the HARQ errors.

7. Scheduling

A scheduling with support for QoS provides for efficient scheduling of UP and CP data.

8. Multiplexing and Mapping

The eNB performs mapping of logical channels onto transport channels.

9. Physical layer functionality

The eNB handles the physical layer such as scrambling, Tx diversity, beamforming processing and OFDM modulation. The eNB also handles layer one functions like link adaptation and power control.

10. Measurements and reporting

eNB provides functions for configuring and making measurements on the radio environment and eNB-internal variables and conditions. The collected data is used internally for RRM but can be reported for the purpose of multi-cell RRM.

Good PDF Document on LTE Functionality

How to get HSDPA users in Ericsson System?

2012-06-16T08:04:00.000+05:30

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

How can I find RRU Type in Ericsson NodeB?

2012-06-14T07:57:00.001+05:30

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

UMTS/HSPA to LTE Migration

2012-05-29T07:49:00.002+05:30

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

Atoll to Google earth

2012-05-28T07:02:00.000+05:30

Atoll to Google earth
Very Good Tool to export data from Atoll to Google Earth.

Download Tool and Guide Here

RRC Establishment Causes

2012-05-03T21:02:00.001+05:30

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

What are Events that can trigger the HSDPA Cell Change?

2012-04-08T05:30:00.000+05:30

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

_{HSDPA Optimization

HSDPA Planning}

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?

2012-04-07T06:00:00.000+05:30

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)

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

2012-04-05T06:00:00.000+05:30

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

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

2012-04-04T05:30:00.000+05:30

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?

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?

2012-04-03T08:30:00.000+05:30

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

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

2012-04-01T19:28:00.000+05:30

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?

2012-04-01T17:37:00.001+05:30

· 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