Alcatel-Lucent proprietary and confidential.

Copyright 2013. All rights reserved.

ALCATEL-LUCENT ENODEB ARCHITECTURE WHITE PAPER

ALCATEL-LUCENT ENODEB ARCHITECTURE WHITE PAPER

Alcatel-Lucent proprietary and confidential. Copyright 2013. All rights reserved.

Page 2 of 4

GENERAL ARCHITECTURE

The eNodeB is an integrated system, composed of a cabinet, a baseband unit (BBU), and RF modules:

TRDUs & RRHs

From an architecture point of view, two types of eNodeB can be found:

Macro eNodeB, based on TRDUs (Transmit Receive Duplex Unit)

Distributed eNodeB, based on RRHs (Remote Radio Heads)

In both cases:

The separation between digital and RF processing is ensured through CPRI interface,

The digital processing is ensured by the BBU (Base Band Unit), the BBU architecture being the same for compact and distributed eNodeBs.

The 9926 BBU could consist in five types of boards and/or module:

The BBU shelf, including the RBP (Rack Back Plane)

The bCAM2, a combined controller and modem board. The bCAM2 is based on programmable integrated devices (System On Chip) providing most of the board processing capabilities (CPU cores, DSP cores, HW accelerators for L1 and transport). The bCAM2 is intrinsically a signal processing board populated with additional backhaul connectors and components.

The bCEM2 which controls part of call processing and base band transmit/receive digital signal processing. Depending on the eNodeB configuration, up to three bCEM2 could be fitted in the BBU shelf.

The RUC (Rack User Commissioning) also known as Fan Rack unit, which supports all commissioning of non-volatile memories, and fans.

ALCATEL-LUCENT ENODEB ARCHITECTURE WHITE PAPER

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RADIO MODULES ARCHITECTURE The dual PA radio modules (TRDU or RRH) are single sector, self-contained radio module, including:

Two transmitters

Two Multi-Carrier Power Amplifiers (MCPAs)

Two duplexing systems

Two receivers

An optical interface

A power system

An AISG controller

The TRDU and the RRH deliver up to 120W nominal composite RF power at the antenna ports (2x 60W). The functional architecture of the radio units is depicted in the following figure:

In downlink, the radio unit receives the optical signal from the digital eNodeB in accordance with CPRI format. The signal is converted into an electrical digital base band signal, which then go through several digital processing functions (filtering, digital up-conversion, peak power reduction, digital pre-distortion). The resulting digital signals are then digital to analogue converted, followed by up-conversion to a pair of RF signals. The RF signals are amplified through power amplifiers and fed to the duplexers. The radio unit continuously measures the transmit RF power and has the capability to monitor VSWR.

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In uplink, two signals are received from the main and diversity antennas. They are amplified by low noise amplification chains, then down-converted before being converted into digital signals. The resulting digital signals go through various digital processing functions (digital down-conversion, filtering), and are then multiplexed according to the required CPRI format and converted into optical signals that are sent to the digital eNodeB. The radio unit has two antenna ports: each port is connected to a duplexer, which provides the necessary isolation to connect the transmitter and one receiver on the same antenna. The two antenna ports enable Tx diversity (MIMO) and Rx diversity.

3 variants of optical fibre are available, depending on the characteristics required. Selection of which fibre to use is by choice of separately ordered optical transceivers:

Multi-mode optical fibre, using separate fibres for outbound (digital unit to RRH) and

inbound (RRH to digital unit) data, provides transmission over distances of up to 500m. This solution

is suitable for the majority of deployments, whether tower-top, building mounted or closely

distributed.

Single mode optical fibre, using separate fibres for outbound (digital unit to RRH) and

inbound (RRH to digital unit) data, provides transmission over distances of up to 20km. This

solution is more costly, but supports deployments where the RRH is a considerable distance from

the RRH, such as linear deployments along highways or in tunnels, or for areas needing remote

coverage.

Single mode optical fibre, using a single fibre for both outbound and inbound data,

provides transmission over distances of up to 20km. This solution is more costly, but supports

deployments where the RRH is a considerable distance from the RRH, such as linear deployments

along highways or in tunnels, or for areas needing remote coverage. Use of only a single

fibre minimises fibre rental costs, where this is a deployment factor