Asset LTE.pdf

Asset LTE- Practical's / Demostrations

Copyright 2011 AIRCOM International

WELCOME

INSTRUCTOR - GRAHAM WHYLEY


LTE – Frequency Bands


LTE – Frequency Bands


LTE – Frequency Bands Supported Channels (non-overlapping) E-UTRA Band

* X -

Downlink Bandwidth

Channel Bandwidth (MHZ)

1.4 3 1 60 2 60 42 20 3 75 53 23 4 45 32 15 5 25 17 8 6 10 7 70 25 8 35 11 9 35 10 60 11 25 12 18 12 6 13 10 7 3 14 10 7 3 ... 33 20 34 15 35 60 42 20 36 60 42 20 37 20 38 50 39 40 40 100 UE receiver sensitivity can be relaxed Channel bandwidth too wide for the band Not supported

5 12 12 15 9 5 2 14 7 7 12 5 3* 2* 2*

10 6 6 7 4 2* 1* 7 3* 3 6 2* 1* 1* 1*

15 4 4* 5* 3 X 4 2* 4 1* X X

20 3 3* 3* 2 X 3* 1* 3 1* X X X

4 3 12 12 4 10 8 -

2 1 6 6 2 5 4 10

1 1 4 4 1 3 6

1 X 3 3 1 2 5


LTE – Frequency Bands E-UTRA Band

Bandwidth UL (MHz)

E-ARFCN UL

Bandwidth DL (MHz)

E-ARFCN DL

Duplex Mode

1

1920-1980

13000 – 13599

2110-2170

0 – 599

FDD

2

1850-1910

13600 – 14199

1930-1990

600 - 1199

FDD

3

1710-1785

14200 – 14949

1805-1880

1200 – 1949

FDD

4

1710-1755

14950 – 15399

2110-2155

1950 – 2399

FDD

5

824-849

15400 – 15649

869-894

2400 – 2649

FDD

6

830-840

15650 – 15749

875-885

2650 – 2749

FDD

7

2500-2570

15750 – 16449

2620-2690

2750 – 3449

FDD

8

880-915

16450 – 16799

925-960

3450 – 3799

FDD

9

1749.9-1784.9

16800 – 17149

1844.9-1879.9

3800 – 4149

FDD

10

1710-1770

17150 – 17749

2110-2170

4150 – 4749

FDD

11

1427.9-1452.9

17750 – 17999

1475.9-1500.9

4750 – 4999

FDD

12

698-716

18000 – 18179

728-746

5000 – 5179

FDD

13

777-787

18180 – 18279

746-756

5180 – 5279

FDD

14

788-798

18280 – 18379

758-768

5280 – 5379

FDD

...

…

…

…

…

33

1900-1920

26000 – 26199

1900-1920

26000 – 26199

TDD

34

2010-2025

26200 – 26349

2010-2025

26200 – 26349

TDD

35

1850-1910

26350 – 26949

1850-1910

26350 – 26949

TDD

36

1930-1990

26950 – 27549

1930-1990

26950 – 27549

TDD

37

1910-1930

27550 – 27749

1910-1930

27550 – 27749

TDD

38

2570-2620

27750 – 28249

2570-2620

27750 – 28249

TDD

39

1880-1920

28250 – 28649

1880-1920

28250 – 28649

TDD

40

2300-2400

28650 – 29649

2300-2400

28650 – 29649

TDD

…


Frame Structures


LTE – Frame Structure


Frame Structures-TDD

0

1

2

3

19 10 ms


Frame Structures-TDD


Frame Structures-FDD

10 ms

0

1

2

3

19 In half-duplex FDD operation, the UE cannot transmit and receive at the same time while there are no such restrictions in full-duplex FDD.

One Subframe = 1 mS


Frame Structures-FDD


LTE Carriers


Supported Channels (non-overlapping)

LTE Carriers

E-UTRA Band

Since the appropriate LTE Frequency Band and LTE Frame Structure have been selected or defined then the Carriers can be defined.

* X -

Downlink Bandwidth



5 12 12 15 9 5 2 14 7 7 12 5 3* 2* 2*

10 6 6 7 4 2* 1* 7 3* 3 6 2* 1* 1* 1*

15 4 4* 5* 3 X 4 2* 4 1* X X

20 3 3* 3* 2 X 3* 1* 3 1* X X X

4 3 12 12 4 10 8 -

2 1 6 6 2 5 4 10

1 1 4 4 1 3 6

1 X 3 3 1 2 5

Bandwidth (MHz)

1.4

3

5

10

15

20

# of RBs

6

15

25

50

75

100

Subcarriers

72

180 300 600 900 1200 Copyright 2011 AIRCOM International

Supported Channels (non-overlapping)

LTE Carriers

E-UTRA Band

Since the appropriate LTE Frequency Band and LTE Frame Structure have been selected or defined then the Carriers can be defined.

* X -

Assign Carrier to Frequency Band

Downlink Bandwidth



5 12 12 15 9 5 2 14 7 7 12 5 3* 2* 2*

10 6 6 7 4 2* 1* 7 3* 3 6 2* 1* 1* 1*

15 4 4* 5* 3 X 4 2* 4 1* X X

20 3 3* 3* 2 X 3* 1* 3 1* X X X

4 3 12 12 4 10 8 -

2 1 6 6 2 5 4 10

1 1 4 4 1 3 6

1 X 3 3 1 2 5

Bandwidth (MHz)

1.4

3

5

10

15

20

# of RBs

6

15

25

50

75

100

Subcarriers

72

180

300

600

900

1200


LTE – Carriers


LTE – Carriers


LTE – Carriers

E-UTRA Band

Bandwidth UL (MHz)

E-ARFCN UL

Bandwidth DL (MHz)

E-ARFCN DL

Duplex Mode

1

1920-1980

13000 – 13599

2110-2170

0 – 599

FDD


LTE – Carriers


Slot Structure and Physical Resources •ONE slot = 12 consecutive subcarriers •One slot = 0.5mS •6 or 7 OFDM symbols (depending upon cyclic perfix size), thus a single resource block is containing either 72 or 84 OFDM symbols •12x 7 = 84 OFDM symbols Copyright 2010 AIRCOM International Copyright 2011 AIRCOM International

LTE – Carriers

Bandwidth (MHz)

1.4

3

5

10

15

20

# of RBs

6

15

25

50

75

100

Subcarriers

72

180

300

600

900

1200


LTE – Carriers

E-UTRA Band

Bandwidth UL (MHz)

...

…

33

1900-1920

34

E-ARFCN UL

Bandwidth DL (MHz)

E-ARFCN DL

Duplex Mode

…

…

…

26000 – 26199

1900-1920

26000 – 26199

TDD

2010-2025

26200 – 26349

2010-2025

26200 – 26349

TDD

35

1850-1910

26350 – 26949

1850-1910

26350 – 26949

TDD

36

1930-1990

26950 – 27549

1930-1990

26950 – 27549

TDD

37

1910-1930

27550 – 27749

1910-1930

27550 – 27749

TDD

38

2570-2620

27750 – 28249

2570-2620

27750 – 28249

TDD

39

1880-1920

28250 – 28649

1880-1920

28250 – 28649

TDD

40

2300-2400

28650 – 29649

2300-2400

28650 – 29649

TDD

…


LTE – Carriers

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0


LTE – Carriers

R1

R0

R0

R1

R1

R1

R0

R1

R1 R0

R0

R0

R1

R0

R0

R1

Configuration of Carrier- 2 antenna


LTE – Carriers


REUSE 1(PRIORITISATION) 15 Mhz

Carrier 1 A1 A1 5 Mhz

A3 A2

A3 Carrier 1

Carrier 1

A2

Each sector divides the available bandwidth into prioritised (one third) and non-prioritised (two third) sections.


REUSE 1(PRIORITISATION) 15 Mhz Carrier 1 A 1 A 1 5 Mh z

Number of Partitions = 3

A 3

A Carrier 1 3

A 2 Carrier 1

A 2

The simplest way to minimize ICI within a Frequency Reuse 1 (FR 1) scenario is by prioritisation of resources. Reuse 1 (Prioritisation) scheme prioritises certain portions of the carrier bandwidth (i.e., number of RBs) in each cell according to a set plan. The whole bandwidth is still available for transmission in all cells, but the concept is that each cell uses its prioritised RBs more often than its non-prioritised RBs, so that it minimises the interference that it may cause to other cells.


Coordination factor The improvement of Traffic & Control SINR with the deployment of Prioritisation is dependent on the Cell Loading and on the coordination factor. coordination factor of 0 assumes no coordination at all. No dB improvement. No ICI coordination factor of 1 means perfect coordination. Recommended 0.7


REUSE 1(PRIORITISATION)


Soft Frequency Reuse



Soft Frequency Reuse Scheme (Power Ratio 50%, Bandwidth Ratio 50%) Copyright 2011 AIRCOM International



inter-cell interference control (ICIC).

The available thresholds are “RSRP” and “Relative RSRP”. RSRP is self explanatory while the latter is defined in dBs and can be expressed as the difference between the RSRPs of the serving and the strongest interfering cell


Global Editor


Reuse Partitioning


Reuse Partitioning •Multiple partitions. •Two dedicated zones, one for CCUs, the other for CEUs. •Each sector can only consume CE resources from its own dedicated CE partition


Comparison


Site Data Base


Bearers


LTE – Bearers


LTE – Bearers

The Default Uplink and Downlink LTE bearers are defined per CQI providing 15 DL bearers and 4 UL bearers.

CQI is a report sent from the UE to the eNodeB suggesting the appropriate Modulation and Coding to be used by the eNodeB Copyright 2011 AIRCOM International

Channel Quality Indicator Reporting Each default Bearers has Control & Traffic SINR requirements according to PDSCH

PUSCH

PUCCH

CQI Report

57

The UE may not have PUSCH resources

CQI

Modulation

Actual coding rate

Required SINR

1

QPSK

0.07618

-4.46

2

QPSK

0.11719

-3.75

3

QPSK

0.18848

-2.55

4

QPSK

308/1024

-1.15

5

QPSK

449/1024

1.75

6

QPSK

602/1024

3.65

7

16QAM

378/1024

5.2

8

16QAM

490/1024

6.1

9

16QAM

616/1024

7.55

10

64QAM

466/1024

10.85

11

64QAM

567/1024

11.55

12

64QAM

666/1024

12.75

13

64QAM

772/1024

14.55

14

64QAM

873/1024

18.15

15

64QAM

948/1024

19.25 Copyright 2010 AIRCOM International


Channel Quality Indicator Reporting

15 Defaulf Bearers PDSCH

PUSCH

PUCCH

CQI Report

57

The UE may not have PUSCH resources

CQI

Modulation

Actual coding rate

Required SINR

1

QPSK

0.07618

-4.46

2

QPSK

0.11719

-3.75

3

QPSK

0.18848

-2.55

4

QPSK

308/1024

-1.15

5

QPSK

449/1024

1.75

6

QPSK

602/1024

3.65

7

16QAM

378/1024

5.2

8

16QAM

490/1024

6.1

9

16QAM

616/1024

7.55

10

64QAM

466/1024

10.85

11

64QAM

567/1024

11.55

12

64QAM

666/1024

12.75

13

64QAM

772/1024

14.55

14

64QAM

873/1024

18.15

15

64QAM

948/1024

19.25 Copyright2011 2010 AIRCOM International Copyright AIRCOM International

coding rate CQI

Modulation

Efficiency

Actual coding rate

Required SINR

1

QPSK

0.1523

0.07618

-4.46

2

QPSK

0.2344

0.11719

-3.75

3

QPSK

0.3770

0.18848

-2.55

4

QPSK

0.6016

308/1024

-1.15

5

QPSK

0.8770

449/1024

1.75

6

QPSK

1.1758

602/1024

3.65

7

16QAM

1.4766

378/1024

5.2

8

16QAM

1.9141

490/1024

6.1

9

16QAM

2.4063

616/1024

7.55

10

64QAM

2.7305

466/1024

10.85

11

64QAM

3.3223

567/1024

11.55

12

64QAM

3.9023

666/1024

12.75

13

64QAM

4.5234

772/1024

14.55

14

64QAM

5.1152

873/1024

18.15

15

64QAM

5.5547

948/1024

19.25

The coding rate indicates how many real data bits are present out of 1024 while the efficiency provides the number of information bits per modulation symbol. 602/1024 = 0.5879 QPSK = 2bits Efficiency= 2x0.5879=1.1758 data bits per symbol Copyright 2011 AIRCOM International

coding rate CQI

Modulation

Efficiency

Actual coding rate

Required SINR

1

QPSK

0.1523

0.07618

-4.46

2

QPSK

0.2344

0.11719

-3.75

3

QPSK

0.3770

0.18848

-2.55

4

QPSK

0.6016

308/1024

-1.15

5

QPSK

0.8770

449/1024

1.75

6

QPSK

1.1758

602/1024

3.65

7

16QAM

1.4766

378/1024

5.2

8

16QAM

1.9141

490/1024

6.1

9

16QAM

2.4063

616/1024

7.55

10

64QAM

2.7305

466/1024

10.85

11

64QAM

3.3223

567/1024

11.55

12

64QAM

3.9023

666/1024

12.75

13

64QAM

4.5234

772/1024

14.55

14

64QAM

5.1152

873/1024

18.15

15

64QAM

5.5547

948/1024

19.25

The coding rate indicates how many real data bits are present out of 1024 while the efficiency provides the number of information bits per modulation symbol. 602/1024 = 0.5879 QPSK = 2bits Efficiency= 2x0.5879=1.1758 data bits per symbol Copyright 2011 AIRCOM International

Coding rate


Bearers


Bearers


MIMO - Multiple Input Multiple Output


MIMO - Multiple Input Multiple Output •The propagation channel is the air interface, so that transmission antennas are handled as input to the channel, whereas receiver antennas are the output of it

MIMO Types

Number of Antennas

SISO

MISO

SIMO

MIMO

(Single Input Single Output)

(Multiple Input Single Output

(Single Input

(Multiple Input

Multiple Output)

Multiple Output)

…

…

…

…


MIMO LTE supports downlink transmission on 1, 2 or 4 cell specific antenna ports corresponding either to 1, 2 or 4 cell-specific reference signals. On their turn each one of the RS corresponds to one antenna port.

R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0

R0

R0

R0 R0 R0 R0 R0

each antenna is uniquely identified by the position of the reference signals On their turn each one of the RS corresponds to one antenna port.

R0

R0

R0

R1

R1

R1 R1

R1 R1

R1

R0

R1 Copyright 2011 AIRCOM International

MIMO • Single antenna port; port 0 • Single User – MIMO • Transmit diversity • Open loop spatial multiplexing • Closed loop spatial multiplexing • Multi User – MIMO • Closed-loop Rank=1 pre-coding


Tx diversity: The first and simplest downlink LTE multiple antenna scheme is : Open-loop Tx diversity. It is identical in concept to the scheme introduced in UMTS Release 99. 010100

010100

T X

R X

SU-MIMO

010100

Closed loop Tx diversity The more complex, closed loop Tx diversity techniques from UMTS have not been adopted in LTE, which instead uses the more advanced MIMO, which was not part of Release 99.


Open-loop spatial multiplexing, no UE feedback required SU-MIMO includes : conventional techniques such as Delay (cyclic for OFDM) Diversity •In open loop in which no feedback is provided from UE configuration collapse’s to time diversity and relies on Cyclic Delay Diversity (CDD) •Creates multi-path on the received signal. Prevents signal cancellation

In case of UEs with high velocity, the quality of the feedback may deteriorate. Thus, an open loop spatial multiplexing mode is also supported which is based on predefined settings for spatial multiplexing and precoding. Copyright 2011 AIRCOM International

Closed loop Tx diversity SU-MIMO includes :Spatial Multiplexing and Precoded Spatial Multiplexing.

The UE asks for two layersRank Indicator 2 from the enodeB. UE feels it can distinguish between to different layers

PUSCH

Data and Control Multiplexing Layer Mapping Rate Matching

CQI

PMI

4 bit 16 CS

RI

Layer 1

Layer 0

Pre Coding

Code Block Segmentation Turbo Coding

Transport Blocks

Data

Physical Uplink Shared Channel (PUSCH): This physical channel found on the LTE uplink is the Uplink counterpart of PDSCH Copyright 2011 AIRCOM International

SU-MIMO-Spatial Multiplexing Spatial multiplexing allows to transmit different streams of data simultaneously on the same resource block(s) SU-MIMO 010 CW0 CW1 010

100

R X

T X 100

R0 R0 R0 R0

Two code-word streams 2x2 SU-MIMO

Depending on the pre-coding used, each code word is represented at different powers and phases on both antennas.

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

Each antenna is uniquely identified by the position of the reference signals Copyright 2011 AIRCOM International

Single user MIMO principle 4 Closed-loop spatial multiplexing Closed-loop spatial multiplexing. Here the UE reports both the RI and index of the preferred pre-coding matrix.

Spatial Multiplexing does increase throughput but this comes at an expense of higher SINR requirements as shown on the LTE bearers

Rank Indicator (RI) is the UE’s recommendation for the number of layers, i.e. streams to be used in spatial multiplexing. RI is only reported when the UE is operating in MIMO modes with spatial multiplexing Copyright 2011 AIRCOM International

Spatial Multiplexing - Rate Gain Spatial Multiplexing (SM) targets increasing users’ throughput. Depending on the number of TX and RX antennae the user experiences a Rate Gain


Single user MIMO principle Spatial Multiplexing does increase throughput but this comes at an expense of higher SINR requirements as shown on the LTE bearers SU-MIMO

SU-MIMO Tx Diversity

This is the coverage area for SU-MIMO

Roughly speaking Diversity is used to improve coverage

+22dB Copyright 2011 AIRCOM International

Single user MIMO principle When applying diversity This is the coverage area for SU-MIMO Spatial Multiplexing (SM) targets increasing users’ throughput. Depending on the number of TX and RX antennae the user experiences a Rate Gain

SU-MIMO

What changes, are the SINR requirements for the bearers that are reduced.


SM is used to increase single users’ throughput


+22dB


Achievable DL Bearer without and with – MIMO Coverage Improvement (2TX by 2 RX)

By increasing the coverage for each bearer respectively the result will be larger areas with higher CQI bearers.


Achievable DL Bearer without and with – MIMO Coverage Improvement (2TX by 2 RX)

So from a system perspective Diversity not only increases coverage but network throughput as well. Copyright 2011 AIRCOM International

SU-MIMO – Diversity SU-MIMO


SM is used to increase single users’ throughput

+22dB


What changes, are the SINR requirements for the bearers that are divided by the corresponding table value


How do we set this up on Asset


Bearers-LTE Parameters

Above this threshold switch to SU-MIMO If enabled

Below this threshold switch to SU-MIMO Diversity

SU-MIMO

SU-MIMO Diversity


Multi User – MIMO


Multi User – MIMO MU-MIMO is used to increase the cells’ throughput. This is achieved by co-scheduling terminals on the same Resource Blocks. Spatial Multiplexing does increase throughput but this comes at an expense of higher SINR requirements as shown on the LTE bearers Copyright 2011 AIRCOM International

Multi User – MIMO

Applying MUMIMO will make no obvious changes to a network unless it is overloaded.

In order for MUMIMO to be used there is a higher Traffic & Control SINR requirement defined Spatial Multiplexing does increase throughput but this comes at an expense of higher SINR requirements as shown on the LTE bearers Copyright 2011 AIRCOM International

MU-MIMO

MU-MIMO increases cell throughput and number of terminals Copyright 2011 AIRCOM International

MU-MIMO Applying MU-MIMO will make no obvious changes to a network unless it is overloaded. To demonstrate the use of MU-MIMO we will spread terminals and run the SIM in snapshot mode. The density of terminals will be high enough for many of them to fail due to insufficient capacity. Then we will enable MU-MIMO and observe how the network is now capable to serve more of the terminals


MU-MIMO

RSRQ changes when MU-MIMO is deployed because the number of served terminals changes.


DL Data Rate without and with MU-MIMO

large improvements close to the cell edge Copyright 2011 AIRCOM International

DL Cell Throughput without and with MUMIMO DL Cell Throughout (per cell) when MUMIMO is enabled.

effect of the eNodeB now being capable to serve a higher number of users by scheduling them on the same resources Copyright 2011 AIRCOM International

The following table indicates how a highly loaded network can accommodate extra users by deploying MU-MIMO.


Bearers Bearers

MU-MIMO is used to increase the cells’ throughput. In order for MU-MIMO to be used there is a higher Traffic & Control SINR requirement defined Spatial Multiplexing does increase throughput but this comes at an expense of higher SINR requirements as shown on the LTE bearers Copyright 2011 AIRCOM International

How do you set MU-MIMO in Asset



Above this threshold switch to SU-MIMO If enabled


SU-MIMO

SU-MIMO Diversity



If enabled

MU-MIMO

SU-MIMO Diversity +18dB Copyright 2011 AIRCOM International


Above this threshold switch to MU-MIMO If enabled


SU-MIMO

MU-MIMO

+22dB

Diversity +18dB Copyright 2011 AIRCOM International

Diversity As previously mentioned Diversity’s main purpose is to increase coverage and this is done by decreasing the bearers’ SINR requirements.

The bearers with the decreased SINR requirements are easier to achieve. When applying diversity the RSRP plot and the SCH/BSC SINR plot stay the same. RSRQ stays the same as well. R0 R0 R0 R0

What changes, are the SINR requirements for the bearers that are divided by the corresponding table value.

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

R0 R0 R0 R0

each antenna is uniquely identified by the position of the reference signals


RSRP RSRP is not affected by cell loads. This is the reason why a network is usually firstly dimensioned to provide adequate signal strength at the desired areas.

WHY?


RSRQ RSRQ on the other hand is affected by cell loads

WHY? Especially with MUMIMO


Comparing all different options for SUMIMO and how they affect Data Rates.


Summary


Terminal Types


Terminal Types


Terminal Types

Path Loss


Path Loss


Terminal Types kTB :thermal noise level , in units of dBm, in the specified bandwidth The receiver Noise Figure (NF) is a measure of the degradation of the SINR caused by components in the RF signal chain. This includes the antenna filter losses, the noise introduced by the analogue part of the receiver SINR (IN)

SINR (OUT)

Ref Sens = KTB + NF + SINR


Link Budget- Up link-Thermal noise Bandwidt Thermal noise h (Δf) power 1 Hz

−174 dBm

10 Hz

−164 dBm

100 Hz

−154 dBm

1 kHz

−144 dBm

10 kHz

−134 dBm

100 kHz

−124 dBm

180 kHz

−121.45 dBm

One LTE resource block

360Mhz

-118.4

Two LTE resource blocks

200 kHz

−120.98 dBm

1 MHz

−114 dBm

2 MHz

−111 dBm

6 MHz

−106 dBm

20 MHz

−101 dBm

Terminal noise can be calculated as:

“K (Boltzmann constant) x T (290K) x bandwidth”.

k = Boltzman constant (1.38*10-23 Joules/Kelvin) T = Temperature in degrees Kelvin R = Resistance in ohms B = Bandwidth in Hz Copyright 2011 AIRCOM International

Terminal Types Bandwidt Thermal noise h (Δf) power 180 kHz

−121.45 dBm

One LTE resource block

Terminal noise can be calculated as: “K (Boltzmann constant) x T (290K) x bandwidth 1.38*10-23 x 290000 x 180000=0.0000 0000 000072034 Convert to dBm = 10 log 0.0000 0000 000072034 -121.45 dBm for one resource block (180kHz)

k = Boltzman constant (1.38*10-23 Joules/Kelvin) T = Temperature in degrees Kelvin R = Resistance in ohms B = Bandwidth in Hz


Terminal Types

DLRS TX Power

Downlink Reference Signal

Reference Signal Received Quality (RSRQ) RSRQ is defined as the ratio N×RSRP / (E-UTRA carrier RSSI), where N is the number of RB’s of the E-UTRA carrier RSSI measurement bandwidth. The measurements in the numerator and denominator shall be made over the same set of resource blocks.


Terminal Types


Terminal Types


Terminal Types


Terminal Types


Traffic Raster


Services


Intoduction QoS differentiation, i.e. prioritisation of different services according to their requirements becomes extremely important when the system load gets higher. The most relevant parameters of QoS classes are: •Transfer Delay • Guaranteed Bit rate: Delay sensitive QoS Classes have guaranteed bit rate requirements. .


Intoduction Allocation and Retention Priority (ARP):

Within each QoS class there are different allocation and retention priorities. The primary purpose of ARP is to decide whether a bearer establishment / modification request can be accepted or needs to be rejected in case of resource limitations . In addition, the ARP can be used (e.g. by the eNodeB) to decide which bearer(s) to drop during exceptional resource limitations


Intoduction Users within the same QoS class and ARP class will share the available capacity. If the number of users is simply too high, then they will suffer from bad quality. In that case it is better to block a few users to guarantee the quality of existing connections, like streaming videos.


Services When running a simulation, ASSET first attempts to serve the GBR demands of both Real Time and Non-Real Time services, taking into account the Priority values of the different services.

Allocation and Retention Priority (ARP)

Resources are first allocated to the service with the highest priority, and then to the next highest priority service, and so on.

If resources are still available after the GBR demands have been met, then different scheduling algorithms can be employed to attempt to serve the MBR of real time services. Copyright 2011 AIRCOM International

LTE QoS


Services

No carrier defined OR BEARER

When running a simulation, ASSET first attempts to serve the GBR demands of both Real Time and Non-Real Time services, taking into account the Priority values of the different services.

After defining the General Service Parameters one or more Carriers can be related to the Service. Since a supporting Carrier has been assigned to the Service, all UL and DL Bearers will be available for selection as the Supporting Bearers.


Services

A Minimum Bit Rate (Min-GBR) and a Maximum Bit Rate (Max-MBR) have been specified for the service. If a terminal achieves connection to one or more of the available bearers then the eNodeB will firstly allocate enough resources to it in order to achieve the MinGBR. It will keep allocating more resources to it until the terminal either reaches the Max-MBR ceiling or until there not more resources available due to cell loading.


LTE – Bearers

The Default Uplink and Downlink LTE bearers are defined per CQI providing 15 DL bearers and 4 UL bearers. The most preferable bearer is DL-CQI-15 and the least preferable bearer is DL-CQI-1


Services

The Default Uplink and Downlink LTE bearers are defined per CQI providing 15 DL bearers and 4 UL bearers


Services

The Default Uplink and Downlink LTE bearers are defined per CQI providing 15 DL bearers and 4 UL bearers


Services

After defining the General Service Parameters one or more Carriers can be related to the Service. Since a supporting Carrier has been assigned to the Service, all UL and DL Bearers will be available for selection as the Supporting Bearers.


Packet Scheduler


Packet Scheduler If resources are still available after the GBR demands have been met, then different scheduling algorithms can be employed to attempt to serve the Max Bit Rate.


Round Robin Scheduler UE 1 Data Request

UE 2 Data Request

UE 6

UE 5

UE 1 Data sent

UE 2 Data sent

UE 3 data Request

UE 4

UE 3 Data sent

UE 4 Data Request

UE3

UE 4 Data sent

UE 5 Data Request

UE 2

The aim of this scheduler is to share the available/unused resources equally among the RT terminals

UE 5 Data sent

UE 1 UE 6 Data sent

UE 6 Data Request

NodeB Buffers

NodeB Packet Scheduler

The Round Robin approach is completely random asit simply allocates the same resources to all terminals in turns. Copyright 2011 AIRCOM International

Proportional Fair If resources are still available after the GBR demands have been met:

Terminals with higher data rates get a larger share of the available resources. Each terminal gets either the resources it needs to satisfy its RT-MBR demand.


Proportional Demand If resources are still available after the GBR demands have been met: The aim of this scheduler is to allocate the remaining unused resources to RT terminals in proportion to their additional resource demands.

Proportional Demand completely ignores RF conditions Copyright 2011 AIRCOM International

Max SINR Terminals with higher bearer rates(and consequently higher SINR) are preferred over terminals with lower bearer rates (and consequently lower SINR). This means that resources are allocated first to those terminals with better SINR/channel conditions, thereby maximising the throughput.

where S is the average received signal power, I is the average interference power, and N is the noise power.

Best RF conditions are served first.


Max SINR Own-signal interference in LTE an occur due to : •Inter-symbol interference due to multipath power exceeding cyclic prefix length •Inter-carrier interference due to Doppler spread (large UE speed) In LTE, orthogonality is often assumed unity for simplicity: a = 1 is assumed for LTE and hence Iown = 0.

where S is the average received signal power, I is the average interference power, and N is the noise power.

Best RF conditions are served first.


The effect of different schedulers on a fairly loaded network

Best RF conditions are served first. Copyright 2011 AIRCOM International

The effect of schedulers on a heavily loaded network

Max SINR Scheduling will maximise the network throughput as terminals with the best RF conditions are served first. Copyright 2011 AIRCOM International

PCI Planning


PCI


PCI

GROUP

CODE

CELL SPECIFIC FREQ SHIFT

0

0

0

0

1

0

1

1

2

0

2

2

3

1

0

3

4

1

1

4

5

1

2

5

6

2

0

0

General


PCI

GROUP

CODE


0

0

0

0

1

0

1

1

2

0

2

2

3

1

0

3

4

1

1

4

5

1

2

5

6

2

0

0

PCI


PCI

GROUP

CODE


0

0

0

0

1

0

1

1

2

0

2

2

3

1

0

3

4

1

1

4

5

1

2

5

6

2

0

0

General


General




Minmise Groups


Minmise Codes


LTE Network Performance- Coverage and Capacity Predictions


Cell Loads Option 1 - Cell loads Site Database and specifically under the LTE Parameters tab in the fields of Downlink Load (as a percentage) and Mean UL Interference Level (in dB)..


Cell Loads The second option is to create a traffic raster spreading the defined LTE Terminal Type(s) and then the cell load levels get calculated by running Simulator Snapshots. In both cases a reference terminal type has to be specified for the calculation process.

Cell load levels get calculated by running Simulator Snapshots.


Cell Loads The second option is to create a traffic raster spreading the defined LTE Terminal Type(s) and then the cell load levels get calculated by running Simulator Snapshots. In both cases a reference terminal type has to be specified for the calculation process.

You must run a traffic raster first


Creating a Traffic Raster

Creating a Traffic Raster This is usually done per clutter type by assigning a terminal density or a relative weight to each one of the clutters.



Creating a Traffic Raster This is usually done per clutter type by assigning a terminal density or a relative weight to each one of the clutters.


Traffic








LTE Simulation - Resolution The decision on what resolution should be used for the simulations is based on what propagation models are assigned to the cell antennas. • Firstly, it is suggested to use a propagation model at the resolution it has been tuned for. Copyright 2011 AIRCOM International

Resolution Secondly, it is suggested to use two propagation models. •The first one (Primary) should be calculated at high resolution (2-20 meters) and for a relatively small radius (1-3 km). • The second one (Secondary) should be calculated at relatively lower resolution (20-100 meters) and for a larger radius (330km).


Array Setting


Path Loss •The first one (Primary) should be calculated at high resolution (2-20 meters) and for a relatively small radius (1-3 km).

The second one (Secondary) should be calculated at relatively lower resolution (20-100 meters) and for a larger radius (3Copyright 2011 AIRCOM International 30km).

Number of covering cells The number of covering cells mainly affects the accuracy of the interference based calculations. The more cells taken into account, the more accurate the interference values are.



Results


Best RSRP


Path Loss


Simulator Results


Simulator Results


Simulator Results

Default Beares


BCH/SCH SINR BCH/SCH SINR is not affected by the cell load. BCH and SCH channels are positioned in the 6 central RBs of the Band Width and effect from interference is small.


RSRQ RSRQ on the other hand is affected by cell loads. WHY?


Diversity When applying diversity the RSRP plot and the SCH/BSC SINR plot stay the same. RSRQ stays thesame as well. What changes, are the SINR requirements for the bearers that are divided by the corresponding table value.

SU-MIMO

SU-MIMO Diversity

+22dB


Diversity When applying diversity the RSRP plot and the SCH/BSC SINR plot stay the same. RSRQ stays thesame as well. What changes, are the SINR requirements for the bearers.

As previously mentioned Diversity’s main purpose is to increase coverage and this is done by decreasing the bearers’ SINR requirements. By increasing the coverage for each bearer respectively the result will be larger areas with higher CQI bearers.

So from a system perspective Diversity not only increases coverage but network throughput as well.

SU-MIMO

SU-MIMO Diversity


Diversity

What changes, are the SINR requirements for the bearers that are divided by the corresponding table value. Copyright 2011 AIRCOM International

Diversity


DL Data Rate Improvement with Spatial Multiplexing

SU-MIMO

SU-MIMO Diversity


Adaptive Switching Diversity and Spatial Multiplexing provide significant gains to the network. Both of them can be deployed at the same time in Adaptive Switching mode by eNodeBs so as to provide higher throughput to users close to the cell and extended coverage to users at cell edge.

SU-MIMO Diversity

SU-MIMO


Simulator Results


Cell Edge Threshold


Cell Edge Threshold (Global Editor)


Asset LTE.pdf

Recommend Documents