Embedded Solutions

Case Study - Design and development of Mobile fading simulator

Customer: Cybernetics - Japan based company specializing in designing application products
Technology: Embedded; FPGA Design

The Customer

Cybernetics is a niche product company, actively involved in designing and developing systems such as Mobile Fading Simulators, Image Processing Systems and micro-controller application products. The Mobile Fading Simulator is used in the test lab of a leading cellular service provider in Japan for performing research.

The Challenge

Cybernetics had an existing VME bus-based system, which used older generation Altera FPGA. This system was very bulky and the VME bus-based system had become obsolete. The client wanted to migrate to a Compact PCI-based system, as better support is available for these systems.

The client provided the block diagram of the multifunction board that was to form the heart of the system. Tata Infotech had to design the board, develop the diagnostics for the board, test and debug the prototype boards. We also had to port the functional FPGA codes to the new system, which comprised twenty boards. We had to perform a unit testing of the various FPGA codes, and also execute the onsite testing and debugging of the entire fading simulator system.

The Solution

The technology used in implementing the solution was the Mobile Fading Simulator. Tata Infotech prepared the detailed requirement specification document and the high-level design document for the multifunction board. The board has two Altera FPGAs Altera APEX 20KE FPGA (EP20K1500E)-1.5 million-gate FPGA devices. The two FPGAs communicate with each other over a 16-bit LDVS bus. The FPGAs interface to EEPROMs, which store look-up tables. These tables are used by the fading simulator algorithms that run on the board. The board has a 1.92 Gbps optical interface and a 384 Mbps x 16 bits LVDS interface. These interfaces are used to interconnect the twenty multifunction boards that make up the fading simulator. A third FPGA interfaces the board to the Compact PCI bus.

The multifunction board is 10-layered with a minimum trace width of 3.94 mils. The EP20K1500E is a 1020-pin FineLine BGA device. Tata Infotech designed the Printed Circuit Board.

Tata Infotech designed the FPGA diagnostics. Tata Infotech developed diagnostics to test all the devices on the boards including the FPGAs, the EEPROMs and the optical transceivers. Diagnostics were also written to test all the hardware interfaces including the interfaces between the three FPGAs.

Tata Infotech designed and developed the Windows NT and Windows 2000 device drivers for the multifunction cards. The device driver allows the host application to access all the FPGA registers, which are used to set the simulation parameters.

Tata Infotech developed the FPGA code for the Signal Generator board, the Fading-Attenuation-Delay Board, the Complex Multiplier Board, the White Gaussian Noise adder board and the DSP Interface Board. The Signal-Tap feature available with Quartus II software was used to perform validation of the FPGA codes.

Later, system testing was performed onsite. The fading simulator comprises of twenty multifunction cards connectors to an embedded Windows NT/2000 PCs having a Compact PCI back plane. A Windows NT/2000 application exercised the system. The results of simulation in terms of the output QPSK data is viewed on an oscilloscope with a Digital to Analog Converter converting the 10-bit, which is selected by rotary switch, Q and I data values to Analog voltage.

Multifunction Board

The Benefits

• Lighter and compact system
• Availability of better support for the system