lte access network

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LTE Access Network

2

LTE Network and Interfaces

EPC

eUTRAN

UMTS/GERAN

WLAN

Internet

S1

SGi

S2 S3,S4

3

eUTRAN Architecture and Interfaces

SGW

eNB

MME

eNB

S1_MME UE and eNB

Signalling

S1_U User Plane Data

App Signalling

S11

X2

Signalling and Control User Data PGW

4

LTE Radio Interface Flexible Bandwidth Options

1.4 – 20 MHz

High Order Modulation and Coding QPSK, 16 QAM and 64 QAM

Adaptive modulation and coding

Robust OFDMA in the Downlink Multi-Carrier Transmission

Good Multipath Performance

Suited to Advanced Antenna Techniques

Efficient SC-FDMA in the Uplink Still good Multipath Performance

Decoding complexity in the eNB

More power efficient than OFDMA

Advanced Antenna Support MIMO, 2x2, 4x4

Beamforming

5

Typical Multipath Environment

OFDMA – Designed to offer good performance

in challenging environments

6

Shannon's Law and Capacity

Low Bandwidth

High Bandwidth

Low SNR

High SNR

7

Capacity in LTE

LTE supports Adaptive Modulation and Coding

Actual Capacity will depend on users location in the cell

SINR is the most important planning KPI

Average cell throughput will lower than quoted

maximums

5

8

The Capacity Planning Problem

100+ Mbps! Assumes good radio signal in

every part of the radio cell

QPSK 16QAM 64QAM

9

User Distribution in the Cell

User Distribution will impact average cell throughput

The resource scheduler in the eNB is very important

Scheduling may be different between vendors

QPSK 16QAM 64QAM

~10% of Area

~15% of Area

~75% of Area

10

The Radio Spectrum

UHF Band is very busy

Most mobile radio services operate in this band

Many frequencies in UHF are designated IMT bands

LTE can be deployed in any IMT Band

TV

TV

GSM

300 500 900 1500 1800 2500 3000 4000 MHz MHz

GSM

UMTS

WiFi

WiMAX

DECT

VLF

Very

Low

Freq

LF

Low

Freq

MF

Medium

Freq

HF

High

Freq

VHF

Very

High

Freq

UHF

Ultra

High

Freq

SHF

Super

High

Freq

3KHz 30KHz 300KHz 3MHz 30MHz 300MHz 3GHz 300GHz

IMT Bands

Shown in White

11

Which Radio Spectrum to Use?

12

13

14

Carrier Aggregation Options (basic)

f1 f2 f3 f4 f5

Band A Band B

a b c

a – intra-band, contiguous (R10 UL only)

b – intra-band, non contiguous (R10 UL Only)

c – inter-band

15

16

Heterogeneous – Dictionary Definition

heterogeneous

/ˌhetərəˈjēnēəs/

- composed of parts of different kinds; having widely

dissimilar elements or constituents

homogeneous /ˌhōməˈjēnēəs/

- composed of similar or identical parts or elements

17

Heterogeneous Network

Large, Small and Tiny Cells

Cells have different technologies with different physical

characteristics

Ideally all layers under the control of a single entity

Pico/

Enterprise Femto

WiFi

CSG Femto

2G

3G

3G/LTE

3G/LTE

3G/LTE

18

Small Cell Capacity Gains