efficient e band transceiver for future networks - tweether · (if + mmw) iq modulator mmw mixer....

Energy Efficient E‐band transceiver for backhaul of the future networks

Project reference: FP7‐ICT‐317957Project Coordinator: CEIT (Spain)Contact Name: Dr. IgoneVélez ([email protected])Start date: 01/12/2012End date: 31/05/2016

mmWWorkshop, Valencia, 2015/11/20 2

Mobile Backhaul requirements

Microwave/ mmW backhaul

Index

E-band transceiver requirements

Results


• Mobile backhaul •connection between cell sites

• core network (controller site)

RANRAN

RAN

Backhaul

Mobile backhaul


Future Networks: C‐RAN

RRH

BBU

CPRI

Antenna

RRH

BBU

CPRI

Antenna

Cell site cabinet

RRH

CPRI

RRH RRH

Fronthaul

Backhaul

Backhaul

CentralizedBBU

Communication between RRH and BBU require a capacity in the order of Gbps


Backhaul network challenges

• Network scale/densification• The introduction of Small cells

•vast expansion of the backhaul network and the number of sites that must be connected and managed.

• Short link length backhaul will be predominant.

• Network capacity• The transition to 5G, and the addition of small cells are all strategies to address growing capacity demand. • The backhaul network must also scale in capacity or risk becoming a bottleneck.

• Network Architecture• C-RAN poses big challenges to the backhaul mainly for Capacity and latency requirements.

Capacity up to 10 Gbps must be backhauled


Mobile Backhaul

• Possible technologies:– Fiber

• It has the capacity and latency requirements of CPRI.• High CAPEX

– Fiber deployment seems to be prohibitively expensive in thecoming years.

– Copper• It does not have enough capacity and presents an excessivelatency to address the requirements of CPRI interconnect.

– Microwave• Best when looking at both the OPEX and CAPEX.



Microwave / mmW backhaul

Index


Results


Traditional Microwave

60 GHz – Unlicensed

Millimetre – E-Band

Frequency Band and spectrum resources for Point‐to‐point link


Available Channel size

The most popular channel sizes are 28MHz and 56MHz

In some Frequency bands channel aggregation is permitted:i.e.: 59‐64GHz up to 2.5GHz

E‐Band: 71‐76 &81‐86GHz ‐ up to 4.75GHz bandwidth‐ Channels of size multiple of 250 MHz

Potential to transmita capacity up to 10 Gbps



Microwave backhaul

Index


Results


• E‐ Band transceiver:– Highly integrated SiGe circuit

E3Network Requirements

81 – 86 GHz

71 – 76 GHz

FDD

Frequency Bands GHz71‐76 Go

81‐86 returnRF interface FDD

Capacity Gbps 10

Network Interface Ethernet 10 Gbps

Latency us 30

Availability at 1km % 99.995


ETSI EN 302 217‐2‐2 Annex Ea: Frequency bands 71 GHz ‐ 86 GHz

Beyond commercial backhaul links

E3Network

E3Network transceiver will increase: • Spectral efficiency


• State‐of‐the‐art E‐band transceivers: GaAs– Cost of mm2 of GaAs is twice that of SiGe– GaAs chips are mechanically fragile

• Difficult machine handling • Increases test costs

– GaAs have much higher defect density• Transceiver in a single chip impossible

– Complicates assembly process– Degrades the reliability of the link

• E3Network: SiGe based single chip FE– Simplify assembly process and improve reliability– Self‐healing techniques to reduce power consumption.

Beyond commercial backhaul links


State‐of‐art: Analogue multi‐line approach

PA

LNAMixers

Mixers

PLL

Dup

lexe

r

Net

wor

kIn

terf

ace

Net

wor

kIn

terf

ace

N ChannelsModulator

Digital dataInput

mmW-Transceiver

IF Module Digital modem• Drawbacks:– Increased area – Power consumption will be penalised.


Selected architecture: Analogue single‐line approach

PA

LNAMixers

Mixers

PLL

Dup

lexe

r

Net

wor

kIn

terf

ace

Net

wor

kIn

terf

ace

mmW-Transceiver

IF Module Digital modemD

emod

ulat

or+

Dec

oder

Enco

der +

Mod

ulat

or

LPFVGA ADC

PLL


Technical specifications

Transmitted signal

characteristics

Number of analogue lines 1Number of digital sub‐bands per analogue line 2Channel separation (MHz) 2000Roll‐off 15%Modulation order 6Code rate 0.875

-3 -2 -1 0 1 2 3-120

-110

-100

-90

-80

-70

-60

-50

-40

GHz

dBW

/MH

z

dbb1 dbb2



Microwave backhaul

Index


Results


Final front‐end of TX (implemented in SiGe 55nm)

PA

Signal generation(IF + mmW)

IQ modulator

mmW mixer


I/Q modulator(implemented in SiGe 55nm)

DescriptionThe IQMOD_CEIT_v1 is a CMOS I&Q modulator up-converter. This deviceprovides a small signal conversion loss of 5dB with -18dBc of sidebandrejection. The circuit up-converts a baseband signal (DC to 3,5 GHz) to afrequency of 15 – 21 GHz, with an output 1-dB compression point of -1 dBm.The required LO power is +16dBm.

Main Specifications

Output Frequency 15 – 21 GHz

BB Input Frequency 0 – 3,5 GHz

LO Frequency 15 – 20 GHz

LO Power +16dBm

OCP1dB > ‐3 dBm (Typical ‐1dBm)

Avg. Conversion Gain ‐5 dB

Input Reflection Coeff. < ‐10 dB

Output Reflection Coeff. < ‐10 dB

DC Power Consumption 61 mW

Chip size 0.98mm x 1.09mm

1.09

mm

0.984mm


mmW TX(implemented in SiGe 55nm)

DescriptionThe EBTX-CEIT-v1 is an E-Band transmitter chip that converts a 16-21 GHzsignal to the 71-76 GHz and 81-86 GHz bands using a 55-65 GHz LO signal.The average conversión gain is 23dB and the maximum output 1-dBcompression point is 14.4 dBm and it is better than 11.2 dBm across both bands.The required LO power is 0dBm for both bands.

Main Specifications

Output Frequency 71 – 86 GHz

IF Input Frequency 14 – 24 GHz

LO Frequency 55 – 65 GHz

Required LO power 0 dBm

OCP1dB > 12.9dBm @ 71‐76 GHz band (max. 14.4 dBm @ 71 GHz)> 11.2 dBm @ 81‐85 GHz band (max. 13.13 dBm @ 81 GHz)

Avg. Conversion Gain 23 dB

Input Reflection Coeff. < ‐7 dB @ 14‐25 GHz

Output Reflection Coeff. ‐12 dB @ 72 GHz, <‐4dB @ 71‐86 GHz


Chip size 2.06mm x 0.79mm

0.79

mm

2.06mm


mmW TX ‐improved version(implemented in SiGe 55nm)

DescriptionThe EBTX-CEIT-v2 is an E-Band transmitter chip that converts a 16-21 GHzsignal to the 71-76 GHz and 81-86 GHz bands using a 55-65 GHz LO signal.It is an improved version of the EBTX-CEIT-v1 transmitter. The averageconversión gain is 23dB and the output 1-dB compression point is higherthan +18 dBm across both bands. The required LO power is 0dBm for bothbands

Main Specifications (simulation values)

Output Frequency 71‐86 GHz

IF Input Frequency 16‐21 GHz

LO Frequency 55‐65 GHz

Required LO power 0 dBm

OCP1dB > 18 dBm

Avg. Conversion Gain 23 dB

Input Reflection Coeff. < ‐10 dB

Output Reflection Coeff. < ‐10 dB


Chip size 2.06mm x 0.79mm0.

79m

m

2.06mm


WP2: Fully‐integrated RX board(implemented in SiGe 55nm)

Signal generation(IF + mmW)

mmW Receiver+ I/Q Demodulator


• High bandwidth (2 GHz)– Challenging DBB implementation in FPGA– High sampling frequency in ADC/DAC– Hard requirements for the base‐band analogue filters

Selected architecture: Challenges

33dBc @ 1.8GHz10dBc from DAC

response


• Transmitted power spectrum at IF

Measurement Results


Measurements Results of Tx IF Board & mmW& PA

Pout=-7.5dBmPPA ̴ -1.5dBm

P-1dB-Mixer ̴ 0dBm


Measurements Results of Tx IF Board & mmW& PA

Pout=-6dBmPPA ̴ 0dBm

P-1dB-Mixer ̴ 0dBm


• High order modulation (64QAM)– Very sensitive to transmission impairments

•Phase noise• I/Q imbalance

– Challenging requirements for SiGe based analogue components•Compensation techniques must be applied in a mixed‐signal approach – self‐healing algorithms required

Selected architecture: Challenges


• TX I/Q imbalance compensation

Self‐healing : TX I/Q imbalance compensation

Effect of I/Q imbalancewithout self-healing (IRR=28 dB)

Correction of I/Q imbalancewith self-healing (IRR>35 dB)


• Extracted gain and phase imbalance variation over time

– Measurements taken in 8 different days:

– Gain and phase imbalance of thesystem vary very slowly over time

– Calibration routine can be done fromtime to time

Self‐healing: TX I/Q imbalance compensation


• Constellation at the receiver

Rx Measurement Results

Real-1 -0.5 0 0.5 1

-1

-0.5

0

0.5

1

Window 17, DS1 payload, Equa


• C‐RAN poses big challenges to the backhaul in Capacity and latency requirements:– Capacity up to 10 Gbps must be backhauled

• Millimetre wave technology working at E‐band is able to transmit 10 Gbps.– Using a SiGe transceiver + self‐healing techniques

Conclusions

Energy Efficient E‐band transceiver for backhaul of the future networks

Project reference: FP7‐ICT‐317957Project Coordinator: CEIT (Spain)Contact Name: Dr. IgoneVélez ([email protected])Start date: 01/12/2012End date: 31/05/2016

efficient e band transceiver for future networks - tweether · (if + mmw) iq modulator mmw mixer....

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