NEC Portugal, a subsidiary of NEC Corporation, has installed a microwave radio link between the islands of Sao Tome and Principe, providing twenty 2 Mbps channels for GSM mobile communications and a minimum of 300 Mbps for IP data communications using the 4 GHz band with 64QAM modulation. This project was awarded to NEC by CST (Companhia Santomense de Telecomunicacoes).
The connection covers 176 km, making it the longest 4 GHz microwave radio link ever deployed by NEC over the sea with IP technology. Previously, the island of Principe was supported by TDM technology delivering just 2 Mbps channels. The new solution implemented by NEC uses Adaptive Modulation Radio (AMR) technology, which enables stable transmission even under rough weather conditions, enabling it to achieve a maximum capacity of 560 Mbps under favorable climatic conditions. This almost doubles the bandwidth available for data communications when compared to the original project specification, which intended to achieve at least 300Mbps bandwidth available with the 64QAM modulation.
NEC has 20 years of experience in designing, planning and implementing microwave projects in Portugal, and Portuguese-speaking countries such as Timor and now Sao Tome and Principe. The company implemented the solution in just five weeks using its long-haul microwave radio system, the NEC DMR 5000iPS.
A youthful African nation which this year celebrates its 40th anniversary, Sao Tome and Principe consists of two islands of volcanic origin and a number of smaller islets. It is a key producer of cocoa with a growing tourism industry. Commercial oil production is expected to begin within a few years. Better mobile voice and data coverage will play a key role in supporting growth in these and other sectors.
