PA Consulting Group Develops an LTE PHY for Catapult Communications

1. An LTE PHY for Catapult
Communications
Catapult Communications is a leader in the field of Network Test Equipment.
Catapult’s products are used around the world to test developments and
implementations of advanced digital communications systems. Catapult’s latest
product is the patent-pending LTE User Equipment (UE) Simulator, the t600
platform, equipped with the LTE UE Sector Card Sets, that work as a peripheral
platform to the Catapult DCT2000®. This platform uses a Physical Layer
interface to connect to the target eNode B.
Case study

2. Figure: 1
Standards
Test vectors
Architecture
IP Cores Control
DSP Signal Chains
Test
And
Integrate
FPGA Signal Chains
IP Cores Interface Control
PA worked with Catapult to devise the most effective solution. The requirements
included fast development, high throughput, flexibility for performance and upgrade
and effective interfaces to the higher layers of the test system and to the target
unit-under-test.
PA carried out a 6 week design study, aiming to plan an effective architecture,
which could meet all these requirements and could deliver a program with minimum
project risk and optimised costs.
Architecture
The selected architecture uses a mixture of DSP and FPGA, built within a µTCA
chassis. The µTCA approach gives great flexibility and granularity, permitting later
system enhancements and easy field maintenance. The DSP FPGA split reflects the
nature of the LTE system. Intensive front end signal processing ( FFT, iDFT, Turbo etc)
is handled in the FPGA while the DSP runs upper PHY functions, and all the control
plane activities.
The architecture presents Catapult with the greatest flexibility, both in the system build
(where extra cards can be used to increase capacity) and in the development process
(where functional testing is simplified by the distributed approach).
Development Program
PA’s development program used a small dedicated team of communications professionals
specialising in the rapid development of complex systems. The team shared design
decisions and worked to minimise development risk and maximise productivity, through
agile development methods and a highly parallel set of development tasks.

3. “ PA’s role in the development of our LTE test system has been a great help in
meeting our overall objectives. Their approach to fast-track development has
been outstanding, and has delivered an LTE PHY right on time.”
Kalyan Sundhar,
Catapult’s VP Engineering
Reset from FiNE(TBC) On-board LEDs
FPGA Top Level
On-board
oscillator(s) D/L (Rx) Signal Chain Wrapper
D/L (Rx) Signal Chain
Clock Debug LED
Reset Control
Generation driver
PLL Locked
Common Memory
Input Buffer Output Buffer IRQ I/O
Register File Interface
Async. Serial (debug messaging )
RS232
DDR2
DDR2
Phy
RS-232
header
Bank 0
Controller
Interface/Control Wrapper
Version Block
(auto-updated)
System Interconnect
Doorbell
Slave
Doorbell
Nios Subsystem
IRQ
Register File
System Interconnect
Sys. Mnt.
Test Mux. Cfg.
Slave
Backplane 4x sRIO
sRIO Endpoint
Resets
Register
Decode
File
Fast System Interconnect
IO Write
Control
Master
Message Ext.
Queue Bridge
I/O Write
IO Read
Master
Decode/Mux
I/O Read
LA Breakout Mezzanine
DDR2
DDR2 Controller
Bank 1
Mictor
Mezzanine
Mezzanine
Connector
Connector
Common Memory
Input Buffer Output Buffer IRQ I/O
Register File Interface
Test Multiplexer Config.
Mictor
U/L (Tx) Signal Chain
Test Nodes U/L (Tx) Signal Chain Wrapper
Signal Chain FPGA Top Level
Key ETS -08 -0102 -D_A 1
Avalon MM Data Plane(fast) Avalon MM Control Plane(slow)
The work was able to draw on key supporting IP elements from leading silicon vendors
– Freescale and Altera. The Freescale 8144 processor provides a high performance
system, with quad-core DSPs delivering 16,000 16-bit MMACS per device. The Altera
EP2S130 offers a super high density array, supported by key IP blocks suitable for the
OFDM environment.
The program has gone from start to a customer-delivered operational PHY in less than
10 months. PA has provided Catapult with access to early versions of the system in order
to allow the system integration to proceed in parallel. Joint integration has taken place,
using common test vectors, and leading to a reliable, well understood platform. PA has
helped transfer PHY level knowledge to Catapult to enable design evolution.

4. “PA’s assistance has been vital for Catapult to deliver
our LTE Test solution to customers on time. PA has
shown excellent understanding of LTE technology
and been responsive to our needs.”
James Rankin,
Catapult’s LTE Product manger
Standards and functions
The work has tracked the LTE standards, with upgrades to account for 3GPP
Release 8 May, June, September and December 2008 documents (an upgrade to
version 8.5 is in development). The code has been enhanced to provide various
Corporate headquarters
levels of instrumentation and control, to allow additional modes of operation of the 123 Buckingham Palace Road
final test system. London SW1W 9SR
United Kingdom
Tel: +44 20 7730 9000
Benefits for Catapult Fax: +44 20 7333 5050
E-mail: info@paconsulting.com
The work has allowed Catapult to make a major move into a new and fast moving
market sector. The PA team has injected a breadth of knowledge of LTE and its Cambridge Technology
Centre
operation and has enabled the Catapult team to concentrate on core business
Melbourn
– the higher layer testing methodology, built upon their proven DCT2000 test system. Herts SG8 6DP
Tel: +44 1763 261222
Fax: +44 1763 260023
Contact: John O’Neill
www.paconsulting.com
PA Consulting Group is a
leading management, systems
and technology consulting firm,
operating worldwide in more
than 35 countries.
For more information on
PA’s wireless offering,
please visit
www.paconsulting.com/
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