Tunnel Coverage Solutions
Coverage systems for tunnel solutions can often be designed using DAS in combination with radiating cable. The precise approach, however, is greatly dependent on installation limitations and challenges. Normally, we may say that tunnel radio planning is 5% radio planning and 95% other challenges.
If you attempt to do the practical work and measurement pre, during and post implementation (and this you should do, with RF planning in a tunnel) you must be prepared to spend many late nights down in the dark; have your orange clothes, boots and hard hat ready . . . . You are going to need them, and a lot of patience, waiting for access to the tunnel.
Tunnel coverage systems pose specific challenges when compared with traditional indoor or outdoor coverage, due mainly to the physical nature of the tunnel itself. Also, the type of vehicle employing the tunnel will affect the design and sometimes the RF properties of this crucial element in the solution; the role of the vehicle is often underestimated, especially when designing coverage solutions for rail tunnel systems. In addition to the specific challenge of handover zones and providing sufficient signal levels, special attention must be paid to the cell layout out and capacity design.
These challenges will be addressed in this chapter, starting with the challenge of interfacing the tunnel coverage system with the normal network via the handover zone. Different layouts of internal handover zones in a tunnel ...