Layered Multi-path Power Control in Underwater Sensor Networks

1. Layered Multi-path Power Control in Underwater Sensor Networks JunfengXu, KeqiuLi, and GeyongMin IEEE Globecom2010 Speak: Huei-Rung, Tsai

2. Outline • Introduction • Goals • Overview • Problem Formulation • Layered Multi-path Power Control (LMPC) scheme • Simulation • Conclusions

3. Introduction • Underwater Sensor Networks (USNs) enable a wide range of important applications • oceanographic data collection • scientific ocean sampling • pollution and environmental monitoring • disaster prevention • assisted navigation • distributed tactical surveillance

4. Introduction • USNs have posed many problems in the design and deployment • limited available bandwidth • large propagation delay • high bit error rates • energy efficiency (especially in the deep ocean) • Many mechanisms have recently been proposed to improve energy efficiency in USNs • design of low-power chipset • optimization of energy model • optimization of source scheduling • development of multi-path communications (MPC)

5. Introduction • Most of the existing mechanisms assume that the sound decay as the propagation distance increases, butignore the noise attenuation in the deep underwater environment • Noise comes from the ocean surface, such as shipping, wind, thermal and turbulence, thus the bottom of the ocean is much ”quieter” than the surface

6. Goals • Taking noise attenuation into account to propose a smart Layered Multi-path Power Control (LMPC) scheme • build an energy-efficient tree-based multiple path • control energy consumption at different nodes in USNs to guarantee the lower energy consumption and higher reliability • avoiding retransmission

7. Overview Radio Channel Acoustic Channel Cross Node Surface Gateway Source Node

8. Problem Formulation transmission power Energy consumed at a node length of data packet packet error rate data rate power data rate of transmission link Lj The objective statement

9. LMPC scheme • Build the energy-efficient tree (EET) • Distribute transmission power on the EET with the proper packet error ratio (PER)

10. LMPC scheme • Build the energy-efficient tree (EET) • binary tree

11. LMPC scheme • Distribute transmission power on the EET with the proper PER AWGN follows normal distribution, instantaneous received signal SNR average received signal SNR of node Nij

12. LMPC scheme • Distribute transmission power on the EET with the proper PER For QPSK modulation, the bit error ratio(BER) is The packet error rate (Prij) of node Nij Aggregated PER of Li

13. LMPC scheme • Distribute transmission power on the EET with the proper PER average power on path Li

14. LMPC scheme no need of retransmission ensure that Prin the range of the average PER of the solution trees The problem can be written as follows

15. Simulation • Use NS-2.29 to evaluate the performance the proposed scheme

16. Simulation Scenario 1 Scenario 2

17. Conclusions • Motivated by the noise attenuation in deep water, this paper has proposed a layered multi-path power control (LMPC) mechanism for USNs in the underwater environment • communication plate is divided into multiple layers • crossed nodes multicast data packets to the next hops • each node can control transmission power itself

18. Thanks For Your Attention~