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3G / UMTS Hot Spots: Tunnels
Types:
- Railway tunnels
- Narrow traffic envelope
- Possible double decker trains
- Train window and wall penetration ?
- Very high speed trains
- Train tracks are in cuts and above ground
- Urban underground tunnel
- Very narrow traffic envelope
- Possible double decker trains
- Train window and wall penetration ?
- Integraded to underground stations
- Car tunnels
- "large" traffic envelope
- Complex configurations with multiple entry and exit ramps
- Short underpasses
- Traffic jams cause massive peak loads
- Pedestrian tunnels
- No penetrations losses
- Indoor power level requirements
- Possible high traffic loads
- Special cases
- Mining applications
- Underground shelters turned in to other venues
- Underground parking complexes
Main Requirement:
Coverage
Typical Solutions:
Longer tunnels require (multiple) active antenna system, possible even multiple base station locations
Medium size systems can be hybrid solutions
Off-Air repeaters popular for short tunnels
Macro base station tabs, where possible
Solution based on cost, not on complexity
Opportunities:
Co-location required to share costs
Urban underground system has heavy traffic
Antenna systems are easy to build while tunnel is still under contruction
Train tracking systems
Typical Risks:
Acquisition
Installation cost for long tunnels high
Normally multiple tunnel installations required to cover a single train line
Return on investment time
Notes:
Customer and owner expectation need to be considered
Might require several base stations / base station locations per tunnel
Based on Petri Possi's Hot Spot presentation
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