AISG Products on WWW.NXP.COM

Remote Antenna Site

Failure Detection

by Site Scanning

Using AISG Modems

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Introduction to AISG

AISG setup in basestation tower today

Embedding AISG functionality in Tower Mounted Devices

Using AISG modems for site scanning

Summary & Conclusions

Further reading….

Content

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Purpose of AISG AISG enables remote control of tower mounted devices by a cellular base station

– Remote Electrical Tilt (RET) setting for antennas

– Tower Mounted Amplifier (TMA) parameter setting

– Status monitoring of tower mounted devices (sensors)

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How does it work ? Control is via RS-485 cable

Smart-Bias-Tees (SBTs) to eliminate the RS-485 cable – from bottom to top of the tower

– RS-485 cables and connectors at bottom and top remain !

AISG signals “inserted” on coaxial RF power cable – 9.6kb/s OOK modulation at 2.176 MHz

Complete specification: www.aisg.org.uk

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Avoiding the cable adds many connectors ! Running an RS-485 cable to the tower top is avoided

But 2 extra RS-485 connectors are added

Plus 4 extra RF power coaxial cable connectors

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Optimizing the AISG system by…. Lowering the number of exposed connectors in the tower increases reliability.

“From testing over 2000 feeder lines, 75% of problems are found in

poor quality, poorly assembled, dirty connectors”.* Other contributors are poor component plating, ferromagnetic materials, connectors not torque correctly.

Connectors are also: – Potential cause of installation errors (wrong connections)

– Expensive compared to the actual electronics

* Source: Electro Rent Europe (http://www.electrorent-europe.com/pim-test/faqs.aspx#q3)

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….putting AISG modems inside

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Eliminates the connectors, but also avoids 2 rugged external Smart-Bias-Tees

Inside the RET antenna housing (or TMA) the electronics are safe

‒ Internal AISG modem electronics cost is much lower than cost of 1 single connector

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Step 1 – Embedding the AISG modem

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ANT

RET

Smart Bias Tee AISG

(RS485+DC)

RF

RF +OOK +DC

INTEGRATED ANT

DC-Bias Tee

Power

ASC3011

ANT

RET

RF

RF +OOK +DC

RF & OOK filter

RF+OOK

Power supply

2.176MHzOOK

UART

New solution replacing Smart-Bias Tee

RS485 Transceiver

AISG (RS485+DC)

No changes to existing RET Software

More cost effective than external Smart-Bias Tee

Eliminate RS485 external connectors

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Step 2 – Combining AISG & RET electronics

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INTEGRATED ANT

ANT

RET + MODEM

DC-BiasTee Power

ASC3101

RF

RF +OOK +DC

RF & OOK filter

RF+OOK

Power supply

2.176MHzOOK

New solution replacing Smart-Bias Tee + CPU (in RET) and in Antenna

PWM

Actu

ator

s

GPIO

Alar

ms/

Se

nsor

s

Mot

orD

river

ANT

RET

Smart Bias Tee AISG

(RS485+DC)

RF

RF +OOK +DC

Eliminate internal RS485 interfaces and components

Eliminate separate RET microprocessor

More cost effective than external Smart-Bias Tee and external RET

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Single band HV Polarized integrated antenna (Present solution)

RF(H Pol) +OOK +DC

AISG MODEM

BTS0

Bias Tee

TX Filter

RX Filter

RX Filter

ANT V

LNA Supervision and Control

Bias Tee

TX Filter

RX Filter

RX Filter

ANT H

RF(V Pol) +OOK +DC

BTS0

RET (MCU)

Com

mun

icat

ion

Pow

er S

uppl

yC

omm

unic

atio

nP

ower

Sup

ply

LNA LNA

Single band HV Polarized integrated antenna with ASC3112

ASC3112

RF(H Pol) +OOK +DC

Modem 0

BTS0

Bias Tee

TX Filter

RX Filter

RX Filter

ANT V

RF

LNA

GPIO/ADC

Bias Tee

TX Filter

RX Filter

RX Filter

ANT H

RF

LNA

OOKOOK

RF(V Pol) +OOK +DC

BTS0

GPIO/ADC

Modem 1

Actuators

PWM

Motor Driver

Ala

rms/

Sen

sors

Power SupplyDC DC

Step 3 – Enable all RF ports with AISG Example: Multiband or a single-band HV polarized antenna

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AISG enabled RF ports enable Site Scanning Strictly speaking for AISG communication, a tower device needs only 1 RF

connector “AISG-enabled”.

Adding an internal AISG modem function all RF ports can be done at low cost

Also avoids fixed port assignments that could result in installation errors

And enables checking the status of the RF connectors by AISG !!

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single controller possible single controller possible

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What’s the Problem ?

Connectivity information tower equipment is gathered manually

Mostly once during installation

Based on visual analysis

Bad connections can be overlooked

Wear out almost impossible to detect

Remote tracing not possible

Increasing tower complexity and

increasing number of connectors

drives the need for a (simple) way to

check all these connections (remotely)

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What’s the Solution ?

Automate the gathering of connectivity data

By electronically scanning the connections

Perform the scan any time remotely without affecting tower operation

Detect improper connections and flag it

Detect damages occurring over time (wear-out)

Site Scan provides way to gather connectivity data remotely. It can have a big impact on the cost of network operations Note: It is not (yet) part of the AISG standard

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Site Scanning – How does it work ? RF, AISG and DC power travel over same cable & connector

Use the existing AISG signalling to also check RF connectors

AISG controller will record connection status per tower device

Each tower device indicates number of ports and connections

AISG controller records all the data to make aconnection map

AISG controller can check this mapping check periodically

Request for “Connectivity Check” can be triggered remotely

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Example of a Site Scan Sequence

Site scan can be initiated by the Basestation (BTS)

Blue blocks are NOT detected yet

Black wires are NOT detected yet

Green blocks mean BTS detected this block

Green wires mean connectivity scanned by BTS

Red oval is the targeted connection

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Site Scan Sequence – Initial state

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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Site Scan Sequence – Address 1st device

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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Site Scan Sequence –1st device responds

Result: – TMA informs BTS it has 4 ports

– 1 out of 2 BTS ports scanned

– 1 out of 4 TMA ports scanned

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ANT device_id_20 0 1

TMA device_id_10

2 3

0 1

BTS device_id_00

0 1

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Site Scan Sequence – Scan next port

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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Site Scan Sequence – Next port scanned

Result: – 2 out of 2 BTS ports scanned

– 2 out of 4 TMA ports scanned

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BTS device_id_00

ANT device_id_20 0 1

0 1

TMA device_id_10

2 3

0 1

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Site Scan Sequence – Address 2nd device

TMA in AISG repeater mode

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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Result: – ANT informs BTS it has 2 ports

– 1 out of 2 ANT ports scanned

– 3 out of 4 TMA ports scanned

– 2 out of 2 BTS ports scanned

Site Scan Sequence – 2nd device responds

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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Site Scan Sequence – Scan next port Horizontal repeater mode

Alternative scan route path

Vertical repeater mode

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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Site Scan Sequence – All ports scanned

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BTS device_id_00

TMA device_id_10

ANT device_id_20 0 1

2 3

0 1

0 1

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In case of failure…..

If devices support repeater mode,

all connections can be traced

Vertical repeater mode should be

supported at all level

Horizontal repeater mode should

be supported at various levels

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Further notes to Site Scanning The number of layers (2 in the example) can be extended to any number

There can be multiple devices per layer

Site scanning can be performed any time without affecting tower operation

AISG communication runs on different carrier without disrupting RF traffic

The software overhead for the basestation controller is low (simple process),

without real-time requirements

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Summary & Conclusions Integrating AISG into tower equipment saves cost of cabling, connectors, SBT’s

and improved overall tower reliability

AISG enabled RF ports bring the extra benefit of implementing site scanning

Site scanning enables simple and low cost remote connection failure detection

Basestation towers becoming more complex, with more connectors increases

potential failure, downtime, and costly fault-finding

Site scanning is NOT part of the AISG standard; needs definition of commands

and scanning procedure.

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For more information and detailed basestation site scanning proposal

See: http://www.nxp.com/documents/white_paper/75017400.pdf

Or contact: AISG.Support@nxp.com

For more information on AISG products

See: http://www.nxp.com/products/interface_and_connectivity/aisg_transceivers_and_controllers/

Further reading…

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