Rev 1

Vanja Plicanicvanja.plicanic@eit.lth.se

Department of Electrical and Information Technology

3G EvolutionChapter:

Rev 1

20Flexible bandwidth in LTE

2009-05-28 3G Evolution - HSPA and LTE for Mobile Broadband 1 Rev 2

Outline

• Introduction• Frequency spectrum for LTE• Flexible spectrum use• Flexible channel bandwidth use• RF requirements for LTE

– BS transmitter– BS receiver– UE transmitter– UE receiver

2009-05-28 3G Evolution - HSPA and LTE for Mobile Broadband 2

Rev 3

Introduction

Spectrum flexibility – key feature of LTE

• Deployment in various frequency spectra (paired and unpaired)

• Deployment in various sizes of frequency spectra

2009-05-28 3G Evolution - HSPA and LTE for Mobile Broadband 3 Rev 4

Allocated frequency bands in paired and unpaired spectra

Frequency spectrum for LTE 1 (4)

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Ex. WCDMA/HSPA Ex. TD-CDMA/TD-SCDMA

LTE

Rev 5

Frequency spectrum for LTE 2(4)

• Reuse of frequency spectra for GSM and IMT-2000• Additional ”new” frequency bands

- 450-470 MHz- 698-806 MHz- 2300-2400 MHz- 2500-2690 MHz- 3400-3600 MHz

Wide frequency operation range450 MHz 3600MHz

2009-05-28 3G Evolution - HSPA and LTE for Mobile Broadband 5 Rev 6

Frequency spectrum for LTE 3(4)

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Paired spectrum

Unpaired spectrum

Rev 7

Frequency spectrum for LTE 4(4)

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450 MHz band 3500 MHz band806-960 MHz band

Rev 8

Flexible spectrum use

Flexibility achieved if following considered:

• Coexistence between operators in the same geographical area in the band

• Co-location of BS equipment between operators

• Coexistence with services in adjecent frequency bands and acrosscountry

• Release independent frequency band principle

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Solution in RF requirements

Rev 9

Flexibility achieved with scalable bandwidth

Flexible channel bandwidth use 1(2)

Pure OFDM signal 90% of the channel bandwidth

(78% for 1.4 MHz case)

Set of bandwidths frequency band dependent

2009-05-28 3G Evolution - HSPA and LTE for Mobile Broadband 9 Rev 10

Flexible channel bandwidth use 2(2)

Solves the problem of spectrum availability and migration into currently used spectra (GSM, CDMA2000 etc.)

- Bandwidths 1.4 MHz and 3 MHz used

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Rev 11

RF requirements for LTE

• BS and UE requirements for transmit and receive performance– Transmitter characteristics: maximum output power, output power

dynamics, transmitted signal quality, unwanted emissionstranmitter intermodulation

– Receiver characteristics: reference sensitivity level, receiver dynamic range , Adjecent Channel Selectivity, receiver blocking, receiver intermodulation, receiver spurious emissions

• Flexibility in bandwidth considered• Regional regulation

– Network signaling of RF requirements for UE – Europe: ETSI, ECC, US:FCC

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BS transmitter requirements 1(2)

Unwanted emissions:- Out-of-band (OOB) emissions- Spurious emissions

Concept of operating band unwanted emissions

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Rev 13

Adjacent Channel Leakage Ratio (ACLR)

- For analysis of coexistence between two systems that operate on adjacent channels (OOB domain)

- Unwanted emissions from components at adjacent channel (PAs)

BS transmitter requirements 2(2)

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BS receiver requirements 1(3)

• Reference sensitivity – How much receiver degrades the SNR of the receiver signal– Defined over 25 resource blocks (5 MHz)

• Receiver dynamic range – To ensure high throughput when receive signal is increased due to

increased interference

From book “LTE, The UMTS Long Term Evolution”

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Rev 15

Receiver susceptibility to interfering signals

BS receiver requirements 2(3)

+ Receiver intermodulation

ICS=In-channel selectivityACS=Adjacent channel selectivity

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BS receiver requirements 3(3)

Adjacent Channel Selectivity (ACS)

Adjacent Channel Interference Ratio (ACIR)

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Rev 17

UE transmitter requirements 1(2)

• UE power level– Terminal power classes (23dBm)– Maximum Power Reduction (MRP)– Additional Maximum Power Reduction (A-MRP)

• Unwanted emission limits– In-band emissions– OOB emissions

• Spectrum Emissions Mask (SEM)• ACLR

– Spurious emissions

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UE transmitter requirements 2(2)

Spectrum Emissions Mask (SEM)

From book “LTE, The UMTS Long Term Evolution”

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Rev 19

UE receiver requirements

• Assumptions:– 2 Rx antennas assumed, 0 dBi gain each– Requirements on MRC combined signal

• Requirements– Similar to BS but different levels – Exception: no in-channel selectivity

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Summary

Various paired & unpaired frequency bands+

Flexibel transmission bandwidth due to OFDM

Spectrum flexibility in LTE

…if considered properly in the physical layer and RF requirements

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