Dedicated to China's wireless telecommunications industry, Beijing Xinwei Telecom Inc. offers advanced telecommunications technologies, systems, and terminal products solutions for local, public, and rural communications and metropolitan area networks. As a full-service company, Xinwei combines product research and development with manufacturing, sales, installation, and after-sales services.

Xinwei's technology revolves around end-to-end, carrier-class solutions for third-generation wireless networks (3G) including the Synchronous Code Division Multiple Access (SCDMA) network technology being adopted on a pilot-program level by all the country's major telecom operators in the five western provinces and the autonomous regions of Sichuan, Shaanxi, Guangxi, Henan, and Inner Mongolia. SCDMA's advantages mainly lie in its high spectrum efficiency, simple structure, flexible network interface, and its excellence in monitoring malfunctions, measuring performance, and system management.

One of the company's goals is to inexpensively provide mobile telephony services to Chinese people in rural areas. Xinwei accomplishes this with its SCDMA McWILL system, which is highly suitable for rural communications, as it is an integrated solution for wireless mobile voice and wide-band data that carriers can sell for a high profit margin with low operational costs. The technology enables voice and data to be transmitted via mobile phone basestations to the Internet.

Xinwei recently began a new project: the development of a new Radio Integrated Access Device (RIAD) that will serve as a wide-band wireless node at the edge of the SCDMA-based IP networks that Xinwei will deploy with its SCDMA McWILL system. Part of a "Country Communication Project," the RIAD system will provide inexpensive voice, data, and FAX services to rural areas of China via SCDMA-connected wireless IP transports. For the new RIAD device, Xinwei needed a signal processor that could excel in price and performance, one that could handle demanding vocoder (voice compression) algorithms and execute software-defined radio (all baseband radio functions) without a hefty price tag.

Xinwei chose a Blackfin® ADSP-BF536 signal processor from Analog Devices, Inc., (ADI) because with the processor's 400 MHz of performance, the company could implement all of its necessary protocols and algorithms in software. Xinwei also liked the Blackfin's strong control management abilities, abundant interfaces, and power management features.

Integrated Services to Rural Areas
Xinwei's RIAD1032A device operates as an integrated access device, providing up to 32 Foreign eXchange Subscribers (FSX) with VoIP access. The system provides integrated voice, fax, and data services into small office, home office (SOHO) and small- to mid-size enterprises through a network of cell phone basestations and the IP network, all at low cost. The voice compression is handled via the RIAD, while data/voice transmission is handled through the SCDMA McWILL IP system software. Xinwei's SCDMA McWILL system is highly suitable in rural areas where deployment of wireless 3G-based data networks is more practical than wireline solutions. The RIAD device, in that context, brings VoIP solutions to SOHO and small- to mid-sized enterprises that may not otherwise have access to this type of technology.

Xinwei was impressed with the price/performance of the Blackfin ADSP-BF536. The signal processor could easily handle the RIAD system software, which includes the uCLinux operating system and driver, VoIP algorithms, application protocols, and production testing software. In its former RIAD system architecture, Xinwei used a Texas Instrument DSP coupled with an ARM processor. With the Blackfin ADSP-BF536, only one processor was necessary to handle both signal processor and MCU tasks.

Blackfin processors embody a new type of embedded processor designed to meet the computational demands and power constraints of embedded communications applications. Based on the Micro Signal Architecture (MSA), Blackfin processors combine a dual MAC state-of-the-art signal processing engine and the advantages of a clean, orthogonal RISC-like microprocessor. Blackfin's unique combination of processing attributes eliminates the need for separate digital signal and control processors, which reduces bill of material (BOM) costs and greatly simplifies hardware and software design tasks. Xinwei says they appreciated the BOM savings and over all cost savings they incurred by using the Blackfin ADSP-BF536 signal processor.

Xinwei also found Blackfin's power management features quite attractive. Blackfin processors provide world-class power management and performance. The processors are designed in a low power and low voltage design methodology and feature on-chip Dynamic Power Management, which is the ability to vary both the voltage and frequency of operation to significantly lower overall power consumption. Varying the voltage and frequency can result in a substantial reduction in power consumption, compared with just varying the frequency of operation. This translates into longer battery life for portable appliances, which is important for products such as Xinwei's, which must operate in rural areas.

In terms of peripherals, Xinwei used the general-purpose I/O connected to the Blackfin ADSP-BF536 signal processor. The Blackfin ADSP-BF536 processor's peripherals are connected to the core via several high bandwidth busses and include functions such as: UARTs, SPI, TWI, timers with PWM (pulse width modulation) and pulse measurement capability, general-purpose I/O pins, a real-time clock, and a watchdog timer. This set of functions satisfies a wide variety of typical system support needs and is augmented by the system expansion capabilities of the part. The processor contains dedicated network communication modules and high-speed serial and parallel ports, and an interrupt controller for flexible management of interrupts from the on-chip peripherals or external sources. Xinwei is also using analog-digital (A-D) and digital-analog (D-A) chips from ADI in its signal chain: the AD9861 and the ADM3202.

Saving Time and Money
Xinwei chose to use uClinux open-source software as the operating system, which is supported on Blackfin processors, saving the company time and money. uClinux offers users royalty-free licenses, plus the availability of drivers, source-code support, tools, ease of portability, and an extensive application base.

Xinwei leveraged ADI's development tools to speed time to market, which was an important consideration. They used VisualDSP++ — an easy-to-install and easy-to-use integrated software development and debugging environment (IDDE) that enables the efficient management of projects from start to finish from within a single interface — to develop their algorithms. They also took advantage of the Blackfin ADSP-BF537 (which is recommended) EZ-KIT Lite Evaluation System and JTAG emulator to develop their hardware board in record time.

Xinwei is thrilled with the price/performance of the Blackfin ADSP-BF536 signal processor, which will help the company deploy much needed VoIP services to rural parts of China in "Internet time." They're so satisfied with the Blackfin that they're planning to use the processor in some of their other communications products in the near future.

For more information on Xinwei, please visit their web site.