BreezeACCESS VL network is cost-effective and requires just two communication points

About JRTT

Based on the "Reorganisation and Rationalisation Plan for Public Corporations" adopted by the Japanese cabinet in December 2001, JRTT (Japan Railway Construction, Transport and Technology Agency) was founded on October 1, 2003, as an Independent Administrative Agency by integrating the Japan Railway Construction Public Corporation (JRCC) and the Corporation for Advanced Transport and Technology (CATT). JRTT promotes the maintenance of Japanese railways and, in particular, the improvement of the Shinkansen (bullet train).

About Rikei Corporation

Rikei Corporation was founded in 1957 to provide best-of-breed IT solutions, systems integration and services to the public and private sectors. The company is listed as 8226 on the #2 Tokyo Stock Exchange. Rikei Corporation is committed to introducing the world's most advanced technologies into the Japanese market. Flagship customers include Japan Defence Agency, KDDI, NEC, NTT-ME and Sanyo Electric. Rikei partners include IBM and HP. Rikei Corporation has more than 200 employees with 7 branches in Japan as well as offices in the US, Hong Kong, Singapore and China.

The challenge

JRTT is currently constructing the 26.455 km Hakkoda tunnel through the 81.2 km extension of the Tohoku Shinkansen (bullet train) from Hachinohe to Shin Aomori. This tunnel is considered to be one of the longest land tunnels in the world and its completion is expected in 2010. A traditional wire hotline telephone network was available in the area; however it limits the communication point and could not provide emergency communications. Furthermore, as construction work is temporary, withdrawal expenses were taken into consideration in addition to the usual construction expenses and therefore using cost effective equipment was a necessity. An additional challenge expected by JRTT was severe tunnel conditions such as multipass, as a result of the curved tunnel architecture, and they required a network that could overcome these difficulties and provide seamless connectivity throughout the tunnel.

The solution

JRTT chose system integrator Rikei Corporation to implement Alvarion's wireless network. Trials to test the network performance began on the eve of January 2007 using Alvarion's BreezeACCESS VL product line in the 5 GHz frequency band. The network consists of a base station installed at the tunnel entrance, two relay stations located inside the tunnel and fourteen mobile stations (thirteen CPEs on moving vehicles and one fixed station). Relay station number 1 is located approximately 10 km away from the base station and relay station number 2 is approximately 10 km further. The relay stations connect to Wi-Fi access points which enable construction workers to communicate using portable IP phones either when stationary or on the construction cars. Outside the tunnel, the public line connects to an IP-PBX which is connected to the base station, enabling the construction workers to communicate with the external office as well.

The result

The network has been fully operational since early May 2007. It has displayed excellent results despite the tunnel being underground, curved and sloped, and overcomes multipass issues using the NLOS functionality in the OFDM based BreezeACCESS VL network. Construction workers can now communicate internally as well as with the external office and tunnel security has improved as the workers are able to provide real time information on escape routes to speed up evacuation in the event of an emergency. The wireless network is cost-effective and requires just two communication points (relay stations one and two) as opposed to cable infrastructure which would require at least ten communication points. Furthermore, the cost effective wireless network equipment enables quick and easy expansion as construction work progresses. This flexible network also allows for additional applications such as data and video to be added in the future should the need arise.

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