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Tuesday, July 13, 2010

PowerPoint Presentation On Underground Communication

PPT On Underground Communication


Underground Communication Presentation Transcript:
Wireless Underground Communication Networks (WUCNs) constitute one of the promising application areas of the recently developed wireless networking techniques. The WUCNs consist of wireless devices that operate below the ground surface. These devices are either (i) Buried completely under dense soil or (ii) Placed within a bounded open underground space such as underground mines and road/subway tunnels.

2. Wi-com through soil using EM waves
EM waves encounter much higher attenuation in soil compared to air. This severely hampers the communication quality. Moreover, the ground surface causes reflection as well as refraction, which requires a comprehensive investigation of the channel model. Therefore, advanced models are necessary to accurately and completely characterize the underground channel and to lay out the foundations for efficient underground communication.

3. Design Considerations
For Channel Signal propagation through soil Pr = Pt + Gr + Gt – Lp Reflection from ground surface Multi-path fading Characteristics of EM waves in soil Modulation scheme Operation frequency and deployment depth Transmit power and volumetric water content

4. Practical Approach
Communications with underground mining vehicles normally are by low frequency FM carrier equipment coupled to the trolley wire of electric locomtives operating on an extensive track system. Low frequency (100 KHz) wireless systems offer good mine coverage by the deliberate coupling of a base Station receiver and transmitter to the mine power system.

5. Paging Systems
It has been observed that it typically takes 30 minutes for a person on the surface to reach a person underground by phone. The primary operational requirement of a communication system is that an individual must be able to initiate and receive communications as necessary regardless of where that person is within the mine. The primary operational requirement cannot be satisfied by adding on to existing mine pager-phone systems, but intermediate paging equipment has been developed that can be added on to existing systems.

 6. Discussion Of System Dual Paging Capability:-
A system center, usually located on the surface, controls and monitors all of the devices associated with the entire HT-220 C giant system system. The center consists of a minicomputer, interface circuitry ,a teletypewriter, and monitor readout devices.

7. Critical Requirements Stability:
Power system stability basically refers to the ability of operating an AC network with all generators in synchronism, retaining synchronism even after a large disturbance

8. Hierarchical Robust
Power System Controller Execution Level Signal pre-processor Actuator / Distributor Operation Level System modal identifier Damping loop Management Level Fuzzy logic based parameter tuner

9. Security
Security refers to the ability of the system to respond only to intended operator commands, blocking all unintended operations.

10. Thanks.

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