MC-TRX White Paper

_________________________________________________________________________________________ Document Issue: v5

Document Status: Released. Date of Issue: July/2010 _________________________________________________________________________________________

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MC-TRX / MC-RRH in Converged RAN

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Alcatel-Lucent MC-TRX and MC-RRH in Converged RAN June 2010

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All rights reserved. Passing on and copying of this document, use and communication of its contents not permitted without written authorisation.

1 Introduction

1.1 Operator Challenges

The current operator challenge is to protect past investments (GSM installed Base Stations) while improving the flexibility of the network to answer end-user expectations for Broadband & Wireless. Operators need to leverage on their existing RAN equipment by introducing agility in their networks, to be able to easily evolve from GSM to W-CDMA or to LTE according to their strategy and spectrum constraints. Networks operations need to be kept as simple as possible and with a cost as low as possible.

Alcatel-Lucent Converged RAN BS

1.2 Benefits of Alcatel-Lucent Multi-Carrier Power Amplifier (MCPA) solution

First it is backward compatible: the MC-TRX has the same form factor as previous generations of transmitters (TWIN TRX, single TRX). It can be plugged in all Alcatel-Lucent BTS cabinets and can be mixed with existing TRX modules. Second to improve GSM scalability inside the Base Station: one MC-TRX module can replace several single carrier GSM modules as it can be configured with up to 6 carriers: 3 TWIN TRX modules of a sector can be replaced by one MC-TRX module. In addition with MC-TRX in a pure GSM configuration, the use of one Power Amplifier for up to 6 carriers in parallel allows to suppress the wideband combiner stage (3 dB loss = 50% of RF power loss) required to feed antenna, resulting in a better power efficiency. Third to be future proof with multi-standard agility. Agility is the result of Software Define Radio (SDR) concepts developed by Bell Labs – Alcatel-Lucent R&D: in multi-mode, the MC-TRX/MC-RRH modules allows for parallel operation of GSM+W-CDMA or GSM+LTE to achieve a smooth migration from 2G to 3G and 4G networks. This multi-standard hardware is a perennial investment even with the final target to switch off the GSM carriers and replace them by W-CDMA or LTE carriers depending on customer needs. The MC-TRX and MC-RRH are both MIMO capable; it ensures the best performances when activating W-CDMA or LTE carriers on these modules. It brings confidence to an operator to deploy the right product in the network. If the majority of wireless subscribers are using GSM, the MC-TRX/MC-RRH will be configured in GSM mode. If the subscribers are moving towards W-CDMA or LTE, it is just a matter of allocating more power to W-CDMA or LTE by simple software reconfiguration.

CONVERGED BS

SDR

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2 Alcatel-Lucent solution

MC-TRX and MC-RRH are the core building block of the Alcatel-Lucent Converged Radio Access Network. This new generation of Multi-Carrier transceiver based on SDR is able to handle carriers from 2 different technologies simultaneously. Both Radio modules are based on the same MCPA technology described below:

� MC-TRX is the classical macro transceiver form factor � MC-RRH is a repackaging of the MCPA technology that fits with a distributed BTS solution.

An Alcatel-Lucent GSM Base Station is easily upgradeable to a Multi-standard Base station by software activation on MC-TRX/MC-RRH to operate in multi-mode (GSM+W-CDMA or GSM+LTE).

2.1 Multi-Carrier TRX (MC-TRX) plug-in module

The new generation of Alcatel-Lucent transceiver “MC-TRX” is an ultra-compact TRX module that can be used in all Alcatel-Lucent BTS cabinets (indoor and outdoor). MC-TRX is a stand-alone module and contains 1 up to 6 GSM carriers with one power amplifier. The upgrade of the Alcatel-Lucent BTS cabinets will result in up to 9 MC-TRX modules in MBI5/MBO2E cabinets and up to 6 MC-TRX modules in MBI3/MBO1E cabinets. One of the main MC-TRX benefits is the full backward compatibility with existing Alcatel-Lucent BTS cabinets:

� Reuse of existing SUM control boards and Antenna Network modules (ANC) � Mixed configurations with previous transceiver generations and MC-TRX

2.1.1 MC-TRX General Characteristics

An MC-TRX is designed to work in a specific GSM frequency band: the MC-TRX900 is addressing the whole GSM 900MHz band and the MC-TRX1800 is addressing the whole GSM 1800MHz band. Their characteristics are shown in the table below:

MC-TRX 900MHz MC-TRX 1800MHz

Working frequency bands

880-915 MHz / 925-960 MHz 1710-1785 MHz / 1805-1880 MHz

Size / Weight Same size and weight as a TWIN TRX

Rx Sensitivity (typical)

GSM: -112 dBm W-CDMA: -125.5 dBm

Instantaneous bandwidth

20 MHz*

MTBF 144 180 h

* With enlarged spectrum frequency span feature, GSM spectrum spread among the complete 900MHz band (35 MHz) can be addressed with 2 MC-TRX modules (B12 candidate feature)

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2.1.2 MC-TRX architecture

The MC-TRX is based on a single Multi-Carrier Power Amplifier as shown below. The different carriers are built at the digital stage, and then amplified through a single multi-carrier power amplifier as show on the picture below:

Digita

l

to the antenna

MCPA architecture

N TRX PA

Digita

l

to the antenna

MCPA architecture

N TRX PA

The multi-carrier technology brings a great flexibility and provides new exciting possibilities:

� Due to the de facto removal of wideband combining of GSM carriers in the path to the antenna

the overall power efficiency of a GSM BTS is increased. Radio power is simply not lost in the

combiner stages anymore.

� A module provides a certain amount of physical output power. Its capability to distribute the

total output power to all carriers gives operators the highest flexibility to convert the radio

transmitted power to coverage or capacity, and this is done by SW adaptation only from OMC.

This power may be distributed over a high number of carriers to provide capacity, focused on a

less number of carriers with higher power per carrier to provide coverage, or it could be shared

between two different radio standards.

� It is possible to emit two radio technologies simultaneously, e.g. GSM+W-CDMA or GSM+LTE on

the same HW module and in the same frequency band (900 MHz or 1800 MHz). This allows a

smooth transition to the next radio technology.

GSMGSM

Same hardware

SDR

multi-mode

module Configure several technologies within

a single module

Att 20 dB*

A

*

*

RBW 30 kHz

VBW 300 kHz

SWT 100 msRef 0 dBm

Center 2.14 GHz Span 30 MHz3 MHz/

*

*1 RM

VIEW

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

GSMW-CDMA

Att 20 dB*

A

*

*

RBW 30 kHz

VBW 300 kHz

SWT 100 msRef 0 dBm

Center 2.14 GHz Span 30 MHz3 MHz/

*

*1 RM

VIEW

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

GSMW-CDMA

LTE

GSM

LTE

GSM

GSMGSM

3G

GSM

3G

GSM

or

SDR capabilities of MC-TRX

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2.1.3 MC-TRX performances

2.1.3.1 MC-TRX Output power

MC-TRX output power depends on the number of carriers configured per module. The following tables describe the output power values in case of pure GSM and Multi-mode configurations.

GSM Carriers GMSK Output power

@ ToC class2

GMSK Output power @ TOC class2

W/ moderate overbooking

8-PSK Output power

@ ToC class2

1 Carrier 67W 67W 45W

2 Carriers 33W 33W 22W





MC-TRX GSM only performances with all carriers at full power Assumes in average 1.3dB loss compared to module level

For LTE only 1 carrier SISO between 40W and 60W per MC-TRX, MIMO implementation requires 2 MC-TRXs. The table below is not exhaustive, but gives some configurations that would make sense on the field when introducing one or several W-CDMA/LTE carriers. The MC-TRX module has the full flexibility to support other mixed configuration in the limit of the Power Amplifier capacity.

W-CDMA GSM + W-CDMA

GSM + LTE

Output power @ module

GMSK Output Power Class 2

GMSK Output power Class 2

with Power Overbooking

1 W-CDMA 1x40W

2 W-CDMA 2x20W

3 W-CDMA 3x20W

1 GSM + 1 W-CDMA 1x21W + 1x54W 1x16W + 1x40W 1x16W + 1x40W



3 GSM + 1 W-CDMA 3x12W+ 1x27W 3x10W + 1x20W 3x11W + 1x20W

4 GSM + 1 W-CDMA 4x10W+ 1x27W 4x8W + 1x20W 4x10W + 1x20W


MIMO 2x2 (Requires 2 MC-TRX)

LTE only 1 LTE Carrier

w/MIMO (2x40W)

2 GSM + 1 LTE (1 GSM Carrier per MC-TRX)

2x32W + 1 LTE Carrier w/MIMO

(2x20W)

2x32W + 1 LTE Carrier w/MIMO (2x20W)



(2x40W)


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(2x20W)


MC-TRX multi-mode performances

2.1.3.2 MC-TRX Power consumption

Several factors influence power consumption of a radio module for entire day:

� Overall output power configured per sector; � Traffic load around the day; � Activation of features such as DTX, Power Control that reduce the power consumption.

The table below shows power consumption of some configurations with MC-TRX in GSM only mode:

Indoor BTS

20% load

3x5 MBI-3 DC

599 W

3x6 MBI-3 DC

554 W

50% load

635 W

590 W

OutdoorBTS

3x5 MBO-1 DC

624 W

3x6 MBO-1 DC

579 W

660 W

615 W

80% load

701 W

623 W

100% load

737 W

662 W

726 W

648 W

762 W

687 W

Indoor BTS

20% load

3x5 MBI-3 DC

599 W

3x6 MBI-3 DC

554 W

50% load

635 W

590 W

OutdoorBTS

3x5 MBO-1 DC

624 W

3x6 MBO-1 DC

579 W

660 W

615 W

80% load

701 W

623 W

100% load

737 W

662 W

726 W

648 W

762 W

687 W

The above table provides MC-TRX power consumption values computed with the following features activated:

� DTX (50% voice inactivity), � Power Control (3dB below BCCH TRX level for non-BCCH TRX), � Adjust Power Voltage (new MC-TRX feature to increase the power efficiency) � Power overbooking activated � Indoor MBI3 BTS and outdoor MBO1 outdoor BTS with DAC @ 25°C in the 900 MHz frequency

band � MCBTS class 2 GMSK output power @ ToC: 17W per carrier with 5 carriers per sector, 14W per

carrier with 6 carriers per sector. The typical power consumption values for MC-TRX 900 MHz in GSM + W-CDMA modes are summarized in the following table:

20% load

3x1 GSM + 3x1 W-CDMA MBI-3 DC

809 W

818 W

50% load

872 W

884 W

80% load

936 W

950 W

100% load

980 W

992 W 3x2 GSM + 3x1 W-CDMA MBI-3 DC

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The above table provides MC-TRX power consumption values computed with the following features activated:

� Indoor MBI3 BTS with d2U in the 900 MHz frequency band � Activation of Downlink DTX (50% inactivity), Downlink Power Control (-3dB on non BCCH TS)

and Adjust Power Voltage � Output power @ ToC: 16W per GSM carriers, 20W for UMTS carrier.

2.1.3.3 Power consumption efficiency comparison of MC-TRX vs.TWIN TRX

The conventional approach via single carrier power amplifier needs 4 x 45W = 180W of RF output power on the module side to provide 4 GSM carriers in one sector. Due to the loss in the necessary wideband combiner the output at Top of Cabinet is 4 x 16W =64W of RF power in this sector. To reach the same result a MC-TRX needs 4x21W=84W of RF output power on the module side. Because there is no combining needed the desired RF output power of 4x16W=64W is also reached at Top of Cabinet. This is illustrated by the figure below:

AN

AN

GSM

GSM

2 TWIN

GSM

GSM

2x16W

2x16W

MC-TRX

AN

AN

4x16W

GSMGSM

4x45W = 180W

@module output

4x16W = 64W

@TOC

4x21W = 84W

@module output

4x16W = 64W

@TOC

MC-TRX benefits come with large GSM configurations, usually configurations with more than 3 TRXs per sector and very high load. The next table summarizes a comparison of MC-TRX versus TWIN TRX modules for different configurations and load:

Configuration Load S333 S444 S666

20% load 3% -7% -35%

50% load -6% -17% -47%

80% load -17% -26% -56%

100% load -23% -32% -59%

MC-TRX900 vs. TWIN TRX900 power consumption gain

2.1.4 Multi-Standard configuration with MC-TRX in Macro BTS

When operator is willing to deploy W-CDMA or LTE technologies in the same frequency band as the GSM band (900MHz or 1800MHz) the most appropriate solution is to consider the MC-TRX module as a shared hardware between both technologies.

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