introduction to lte 4g lte advanced bsnl

1. Introduction to
4G LTE-Advanced
T K Mondal
SDE, NSCBTTC,
BSNL

2. 1. LTE-Advanced: Requirements and New Technologies
2. Carrier Aggregation
3. Coordinated Multipoint Operation
4. Self Organising Network
5. Inter-Cell Interference Coordination

8. LTE Advanced Architecture

9. LTE Advanced HetNet Architecture

11. ◼ Carrier Aggregation increases the channel bandwidth by
combining multiple RF carriers.
◼ Each individual RF carrier is known as a Component Carrier.
◼ The release 10 version of the 3GPP specifications defines
signaling to support up to 5 Component Carriers. i.e. a
maximum combined channel bandwidth of 100 MHz.
◼ Component Carriers do not need to be adjacent and can be
located in different operating bands.
◼ The release 10 version of the 3GPP specifications defines
individual Component Carriers to be backwards
compatible so they can be used by release 8 and release 9
devices.
Carrier Aggregation

12. Carrier Aggregation
❑ Aggregation = Combine multiple bands (Component Carriers)
❑ Backward compatible with LTE (Single carrier)
→Each band can be 1.4, 3, 5, 10, or 20 MHz
❑ Maximum 5 component carriers →100 MHz max
❑ Each component can be different width
❑ Number of components in DL and UL can be different, but
Number of components in DL > Number of components in UL

16. MIMO
❑ 8x8 MIMO in DL and 4x4 in UL
❑ MIMO used only when SNR is high , Good Channel
❑ If SNR is low, other spectral efficiency techniques, such as,
transmit diversity, are used.
❑ Many different transmission modes defined. UE is informed
about the mode to use via signaling
❑ Modes differ in number of antennas, antenna port, precoding
type, type of reference signal
❑ Three new categories of UE: Category 6, 7, 8
Category 8 supports maximum features

18. ❑ 8x8 MIMO in the downlink requires 8 transmit antenna at the eNode B
and 8 receive antenna at the UE. lt provides support for thesimultaneous
transmission of 8 parallel streams of data.
❑ These streams of data are generated from 2 transport blocks which are
processed by the physical layer before a serial to parallel conversion
generates 4 streams from each block. 2 rather than 8 Transport blocks are
used to help keep the signalling overhead to a minimum. 8x8 MIMO for
the downlink.
❑ 4 x4 MIMO in the uplink requires 4 transmit antenna at the UE and 4
receive antenna at the eNode B. It provides support for the simultaneous
transmission of 4 parallel streams of data. These streams of data are
generated from 2 transport blocks which are processed by the physical
layer before a serial to parallel conversion generates 2 streams from each
block.
MIMO Enhancements

19. Coordinated Multi-Point transmission (CoMP)
Coordinated Multi-Point (CoMP) transmission in the
down link and reception in the uplink are LTE-
Advanced solutions to help improve the cell edge
throughput and spectrum efficiency performance.

20. Coordinated Multipoint Operation (CoMP)
❑ To improve performance at cell edge
❑ Base stations coordinate transmissions and reception
❑ Joint Transmission: Multiple transmitters in the same
subframe
❑ Dynamic Point Selection: Transmission scheduled from one BS
❑ Joint Reception: Multiple BS receive the signal from one UE
and combine
❑ UE is informed about different UL/DL decisions

24. A radio access network which includes
macro, micro, pica and femto BTS, as well
as relays and repeaters. This type of radio
access network is known as a
heterogeneous network because it
includes a range of different BTS types.
Heterogeneous network

25. Types of BTS :
◼ Macro BTS :The most common BTS type is the macro BTS,
which 3GPP categorizes as a ' wide area BTS ‘. Macro BTS
having their Antenna above roof top level and Tx power 20 -
40 Watt.
◼ Micro BTS : Micro BTS having their antenna below roof-
top level and Tx power is typically 5 or 10 watt.
◼ Pico BTS : 3GPP categorizes pico BTS as ' local area BTS ' .
Pico BTS are designed to provide coverage across small areas
and transmit power does not exceed 0.25 watt.
◼ Femto BTS : Femto BTS known as ’ home BTS. They are
intended for use at home, or in small offices. Their transmit
power does not exceed 0.1 W.

28. Types of Cells
❑ Cell (MacroCell): Cover a few miles. Public Access. Open Area.
❑ MicroCell : Less than a mile wide. Public Access. Malls, Hotels,
Train Stations
❑ PicoCell : in-Building with public access
❑ FemtoCell : In-Building with restricted access
❑ AttoCell : In-room
❑ ZeptoCell : On-Desk
❑ No milli, nano cells

29. HetNet/Small Cells
❑ Macro eNB: Normal Base Station
❑ Relay Node (RN): Micro or Pico Cell.
❑ HeNB: Home eNB for indoor coverage in homes, offices,
malls. Privately owned and operated. Femto Cell.
❑ Remote Radio Heads (RRH): Relay nodes connected to DeNB
via fiber

30. Heterogeneous network : Repeater
Repeaters can be used to extend the coverage of an
existing BTS. They re- transmit the uplink and
downlink signals without having to decode any of the
content. Repeaters have one antenna directed
towards the donor cell, and a second antenna
directed towards the target coverage area. The target
coverage area could be an indoor location so the
second antenna could be indoors.

31. Relay s also rely upon an RF connection to a
donor cell , but Relays differ from Repeaters
because Relays have their own cells and
their own protocol stack, i.e. a Relay is
similar to a normal BTS but without a fixed
transport connection. Relays decode signals
and make radio resource management
decisions.
Heterogeneous Network : Relay Node

32. Relay Nodes
❑ Relay Nodes: Low-power base stations Used to enhance
performance at cell edges, hot-spot areas, indoor coverage
❑ Donor eNB (DeNB): Primary base station
❑ A modified version of E-UTRAN air interface Uu is defined: Un
❑ Both Donor and Relays may use the same/different frequencies
❑ Self-Interference: Relay transmission may interfere with its
reception on the same frequency Avoided using time sharing
❑ Donor does the mobility management

33. Self Organizing Network-
SON

35. Self-Organizing Network (SON)
❑ User installable.
❑ Not-physically accessible to the carrier
❑ Operator provides femtocell ID. Customer registers location
❑ Self-Configures:
➢ Transmission Frequencies
➢ Transmission Power
➢ Preamble: Identifies the segment (IDcell). Some IDs for reserved for
femtocells. Helps differentiate from macrocell.
➢ Neighbor Cell list: Helps in handover
❑ Turned on/off by the consumer →Dynamic topology

36. Management and Configuration
❑ Self-Configuration
❑ Remote configuration by service provider
❑ Femtocell senses the channel to detect neighboring cells
❑ May broadcast messages for neighbors

37. Enhanced Inter Cell Interference Coordination
( eICIC)
❑ ICIC: A eNB sends a “load information” message to the neighbor
eNB about interference level per physical resource block. The
neighbor adjusts DL power levels at those blocks
❑ Almost Blank Subframes (ABS): Only control channels and cell-
specific pilots, no user data ➔Allows UEs in CRE region to
mitigate macro-cell interference = eICIC

38. CoMP with Small Cells
❑ A UE can get service from multiple BSs (eNB, RN, HeNB, RRH)
➢ Can get data through multiple BSs
➢ Can send data through multiple BSs
➢ Can send data to one BS and receive from another

39. Voice over LTE ( VoLTE)
❑ Original LTE is not circuit switched
❑➔Voice needed to go through GSM or 3G circuits Called Circuit
Switch Fall Back (CSFB) ➔Need dual radios
❑ IP Multimedia Services (IMS) handles the call setup signaling.

40. LTE-Advanced Development History
UMTS
(WCDMA
)
HSPA
HSDPA /
HSUPA
HSPA+ LTE LTE
ADVANC
ED
(IMT
ADVANC
ED)
3GPP
Release
Rel 99/4 Rel5/6 Rel 7 Rel 8/9 Rel 10
Max
Downlink
Speed
384 Kbps 14 Mbps 28 Mbps 100 Mbps 1 Gbps
Max Uplink
Speed
128 Kbps 5.7 Mbps 11Mbps 50 Mbps 500 Mbps
Access
Method
WCDMA WCDMA WCDMA OFDMA/
SC-
FDMA
OFDMA/
SC-FDMA

41. Summary
1. LTE-A meets and exceeds all requirements for 4G as
specified in IMT-Advanced.
2. Three key factors that affect data rate are: spectrum,
spectral efficiency, and cell size
3. LTE-A can aggregate up to 5 carriers to make up to 100 MHz
4. LTE-A has frequency reuse factor of 1 since spectrum is
expensive, uses high-order MIMO.
5. LTE-A uses relay nodes to cover remote areas and hot-spots.
Also allowes Home eNB (Femto cells).
6. Code-book and non-code book precoding improves MIMO
7. Coordinated Multipoint operation (CoMP) allows mitigation
of interference at cell edge. CoMP can also be used with
cross-carrier scheduling.

42. Drive Test

43. What isDriveTesting:
• Drive Testing is a method of measuring and
assessing the coverage, capacity and Quality of
Service (QoS) of a mobile radio network.
• Drive testing is principally applied in both the
planning and optimization
stage of network development.
• Drive tests are the most common measurement
tool used by operators, to probe the quality status
and solve network problems.

44. WhyDriveTesting?
• To check deployment of new network sites in
order to meet coverage, capacity and quality
requirements
• Optimization of the network
• Benchmarking of performance
• Troubleshooting
• To verify the performance after an upgrade or
reconfiguration of the network

45. DriveTesting:
• It is conducted for checking the coverage criteria of the cell
site with the RF drive test tool.
• The data collected by drive test tool in form of Log files are
assessed to evaluate the various RF parameters of the
network.
• The technique consists of using a motor vehicle containing
mobile radio network air interface measurement equipment
that can detect and record a wide variety of the physical
and virtual parameters of mobile cellular service in a given
geographical area.

46. Data Acquiredfrom DriveTest:
The dataset collected during drive testing field measurements
can include information such as
• Signal intensity
• Signal quality
• Interference
• Dropped calls
• Blocked calls

47. DataAcquired from DriveTest…
• Call statistics
• Service level statistics
• QoS information
• Handover information
• Neighbouring cell information
• GPS location co-ordinates

48. Typesof DriveTesting:
1.Network Benchmarking
2.Optimization & Troubleshooting
3.Service Quality Monitoring
The results produced by drive testing for each of
these purposes is different.

49. Network Benchmarking:
• Sophisticated multi-channel tools are used to measure
several network technologies and service types
simultaneously to very high accuracy and collect accurate
competitive data on the true level of their own and their
competitors technical performance and quality levels

50. Optimization andTroubleshooting:
• Optimization and troubleshooting information is
more typically used to aid in finding specific
problems during the rollout phases of new
networks or to observe specific problems
reported by consumers during the operational
phase of the network lifecycle.

51. ServiceQualityMonitoring:
• Service quality monitoring typically involves
making test calls across the network to a fixed
test unit to assess the relative quality of various
services using Mean opinion score (MOS).
• Service quality monitoring is typically carried
out in an automated fashion.

52. Equipmentusedin drivetest:
• Alaptop computer - or other similar device;
• Data collecting software installed on the laptop;
• ASecurity Key - Dongle - common to these
types of software;
• One mobile phone for each mobile network
that is being tested; and
• One GPS antenna.

55. TestMethods:
Test Methods Purpose
Idle It isused to record the network condition at idle state and
the leveland C/I on BCCH
Dedicated _Short Call
(120 sec)
It ismainly used for testing the accessibilityand mobilityof
network.Also used for checkingsuccessful completion of call
Dedicated _Long Call
(entire duration of drive
test)
It ismainly used to test the retainability and sustainability.
e.g.Calldrop rate, Handover Successrate, etc.

56. Analysisof DriveTestData:
• The drive test data is collected through data
collecting software like TEMS.
• TEMS investigation 14.x and above.
• Test Mobile System(TEMS) is a technology used
by telecom operators to measure, analyse and
optimise their mobile networks. It is considered
as basic tool to perform wireless network drive
testing, benchmarking and analysis.

57. KeyPerformanceIndicators:
• Accessibility (Call set-up success rate) (%)
• Retainability (Dropped calls) (%)
• Mobility (Handover success rate) (%)
• RF Coverage (%)
• Rx Quality (%)
• Carrier over Interference (%)

58. Accessibility:
❖Accessibility is the ability of a service to be obtained within
specific tolerances and other given conditions, when requested by
the user. In other words, the ability of a user to obtain the
requested service from the system. Accessibility is monitored by
measuring Call Setup Success Rate (CSSR) which is defined as the
ratio of Established Calls to CallAttempts.

59. R
etainability:
• Retainability is “The abilityof a service,
once obtained, to continue to be provided under
given conditions for a requested duration.” For
determining the Retainabilty the regulation prescribes
three important parameters namely Call drop rate
(CDR), Worst affected Cells having more than 3%
TCH drop and Connection with good voice quality.

60. Mobility:
❖In a cellular system a base station has only a
limited coverage area. Hence it is possible for a
moving subscriber to be out of range of a base
station while making a call. The process by which
a mobile telephone call is transferred from one
base station to another as the subscriber passes
the boundary of a cell is called a handover. The
Handover success rate (HOSR) more than 95% is
considered to be good.

61. RFCoverage:
❖RF Coverage relates to the geographical
footprint within the system that has sufficient
RF signal strength to provide for a call/data
session. The Coverage rate of an operator is
calculated basis of %age of samples in which the
receive level (Rx) is better than -85 dbm at street
level.

62. RxQuality:
• For measuring voice quality, Rx Quality samples on a
scale from 0 to 7 for GSM operators are measured. As
per the TRAI QoS norms, Rx Quality between 0- 5 for
GSM operators is considered to be good, whereas Rx
Quality beyond this benchmark is considered to be poor.
TRAI has set down the QoS norm requiring
connections with good voice quality to be >95%.

63. CarrieroverInterference(C/I):
• The carrier-over-interference ratio seeks to test the level
of optimization of the signal strength of a network. It is
the ratio between the levels of the signal strength of the
current serving cell to that of the signal strength of
undesired or interfering signal components. The
measurement range extends from 0 dB to 30 dB. A C/I
below 4 dB would normally result in a dropped call. The
C/I values between 9 and 15 is acceptable; while values
between 15 and 30 are considered good.

64. Any Question
?