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Volume 4:

3G BTS Systems and NEC Electronics (1/2)

3G mobile phone service area expansion

The mobile phone has become an indispensable item in both our business and personal

lives. Mobile communications are making rapid advancement toward the realization of

multimedia telecommunications services such as videophone and Internet access as well

as still- and moving-picture e-mail. Supporting this advancement are 3G mobile phones

that employ a frequency band with high transmission efficiency (2GHz) and aim to achieve

2Mbit/s (2G: 384Kbit/s) high-speed telecommunications. Revolutionary new

telecommunications services are expected to make their debut in the near future.

However, even the most groundbreaking telecommunications services will not lead to an

increase in the number of users if their service areas are limited. This is why service

providers are expanding their service areas and working to create an environment in

which multimedia telecommunications services can be realized anytime and anywhere. 3G

mobile phone services already cover approximately 96% of Japan's population. Moreover,

service providers are expanding 3G service areas through the installation of base

transceiver stations (BTS) in tunnels, airports, subways, underground malls and other

indoor areas where radio signals could not reach up until now.

Mobile phone system structure

Service area expansion is achieved by

installing wireless BTS, which receive

radio signals from mobile phones, in

numerous locations. The range within

which radio signals from mobile phones

can reach a BTS is referred to as a cell.

This is why mobile phones are sometimescalled cell phones. Even if a mobile phone

moves from one cell to another, the call is

handed off to the BTS that controls the

next cell (handoff function) so that it can

be continued without interruption.

BTS convert the radio signals received

from mobile phones to asynchronous

transfer mode (ATM) protocol and thensend them to a radio network controller

(RNC) that controls multiple BTS. These signals pass through a mobile services switching

center (MSC), which controls mobile phone connections and various services, and are then

sent on to an existing public telephone network. This is how calls are made on a mobile

phone (Figure 1).

With the advent of 3G mobile networking, further reduction in BTS size and weight is

being called for since BTS must be set up in numerous locations to form a network that

can be likened to a mesh net. In addition, plans are now under way to make the transition

to full IP, whereby it will become possible for communications to be carried out using thesame system employed by IP networks, which are representative of the Internet.

Moreover, the smooth transition from ATM to IP systems has become an issue that must

be addressed. Thus, various efforts are currently being made to further the evolution of

Figure 1 Mobile phone system structure

[Enlarged image]

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3G mobile phone systems.

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NEC Electronics and its support of 3G mobile phone systems

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Volume 4:

3G BTS Systems and NEC Electronics (2/2)

NEC Electronics and its support of 3G mobile phone systems

NEC Electronics has created a line of

semiconductor devices for use in wireless

base station construction, and is thereby

contributing to the realization of 3G mobile

phone systems. Our backplane transceiver

LSI chips, the PD98441 and PD98442

(Figure 2), are examples of such devices

and are optimized for backplane

transmission between chips mounted on

different circuit boards in BTS systems.

The Universal Test and Operation PHY

Interface for ATM (UTOPIA) and Packet

Over SONET PHY (POS-PHY) are employed

for data transmission by most chips that

perform conversion or switching in the

control circuit boards used in wireless base stations and communication circuit boards forlinking to the overlying RNC (radio network control). As UTOPIA and POS-PHY are parallel

interfaces that transmit data on 16 or 32 signal lines, engineers are face with problems

such as complex wiring and the necessity of a large surface area for wiring. Our backplane

transceiver LSI devices convert from a parallel interface to a serial interface, and transmit

serial data at speeds up to 880 Mbps on the Low-Voltage Differential Signaling (LVDS)

level. Serial data backplane transmission improves the mounting footprint efficiency,

achieves low power consumption and contributes to reduced system cost.

By combining the PD98442 that has eight channels of LVDS links and the PD98441 that

has two channels of LVDS links, you can construct a star-topology backplane. As bothtransceivers have a mode for using half of the channels for redundant links, you can

construct highly reliable systems.

The PD98442 and PD98441 are ideal for both ATM base network and IP base network

systems such as Digital Subscribe Line Access Multiplexer (DSLAM) systems that bundle

together multiple xDSLs and act as high-speed bridges to large-capacity backbone

networks through routers and other telecommunications systems.

Challenges to high-speed interface IP core (macro) development

The popularity of 3G mobile phone systems has boosted the demand for constructing high-

performance base stations with a short turnaround time and low cost. NEC Electronics is

working to meet the needs of the wireless infrastructure industry and is meeting the

challenge of high-speed interface macro development. Our PD98441 and PD98442

backplane transceivers are examples of such devices that were developed using the high-

speed interface macro.

NEC Electronics has also developed a high-speed interface macro that meets the

specifications of Reference Point 3 (RP3) of

the Open Base Station Architecture

Figure 2 Backplane transceiver[Enlarged image]

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Initiative (OBSAI) intended to standardize

the interface between different base station

modules. The new high-speed macro has

been designed for our CB-130 ASIC

technology. System chips incorporating the

high-speed interface macro meeting the

RP3 specifications can reduce the costs of

BTS system development and system

introduction.(Figure 3)

The RP3 specification defines data rates of

768 Mbps and 1.536 Gbps between the

baseband (signal) processing and radio

components of a wireless base station. Our

new high-speed interface macro is the first

in the industry to handle both data rates.

The macro also conforms to the 10 Gbps Attachment Unit Interface (XAUI) of Ethernet and

InfiniBand standards. Furthermore, the macro handles up to 16 channels. With these

features, our new macro supports optimized system construction to satisfy the demands ofcustomers.

With the development of the high-speed interface macro and LSI chips that incorporate

them, NEC Electronics offers optimized solutions that lead the industry. Our leading-edge

semiconductor technologies will support the evolution of 3G mobile phone systems.

* OBSAI is a group of nearly 70 leading manufacturers of wireless infrastructure

equipment, related modules and components from all over the world.

* InfiniBand is a registered trademark of the InfiniBand Trade Association.

Figure 3 Open Base Station Architecture diagram[Enlarged image]

Links

System Applications

Mobile: Third Generation Mobile Phone

Backbone Communications

Products Communication System

Cell/Packet Serial Transceiver PD98441

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Figure 1 Mobile phone system structure

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Figure 2 Backplane transceiver

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