NEC Portugal, a subsidiary of NEC Corp., 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 a modulation of 64QAM. This project was awarded by Companhia Santomense de Telecomunicacoes (CST).

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 300 Mbps 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.

 "The capacity increase in the link between the two islands is an ambitious achievement that has brought the island of Principe closer to the island of Sao Tome. It has vastly increased the quality of telecommunications services in the island of Principe," said Walker Viana, CST's Technical Director.

 "The design, planning and implementation of a link with these characteristics, over the sea and for a record distance, is always a challenge, given the need to ensure the high levels of performance and quality by which NEC is recognized in the market. However, taking advantage of the technological advances of its equipment and the experience of its engineers gathered over two decades of activity, NEC met this challenge and successfully established this high capacity link between the two islands," said Joao Paulo Fernandes, General Manager, Sales and Marketing, NEC Portugal.

NEC was selected due to the quality of its equipment and the link design it prepared, together with its experience in the management and execution of microwave radio transmission projects. This resulted in a truly competitive solution, capable of ensuring the high performance level required by CST.

A youthful African nation, 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.