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1 Core-PC: A Class of Correlative Power Control Algorithms for Single Channel Mobile Ad Hoc Networks Jun Zhang and Brahim Bensaou The Hong Kong University.

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Presentation on theme: "1 Core-PC: A Class of Correlative Power Control Algorithms for Single Channel Mobile Ad Hoc Networks Jun Zhang and Brahim Bensaou The Hong Kong University."— Presentation transcript:

1 1 Core-PC: A Class of Correlative Power Control Algorithms for Single Channel Mobile Ad Hoc Networks Jun Zhang and Brahim Bensaou The Hong Kong University of Science and Technology TWC 07

2 Outline Introduction Correlative Power Constraints Core-PC Performance Evaluation Conclusion

3 Introduction The energy supply in wireless devices is limited by their battery capacity. From measurements in real systems, – Packet processing only consumes a small fraction – The energy is consumed by the transmission reception listening to the channels

4 Introduction It is important to design power control algorithms that – Improving network throughput – Reducing energy consumption

5 Goal To design power controlled MAC protocols – Throughput better than IEEE 802.11 – Energy consumption smaller than IEEE 802.11

6 Introduction All previous works on power control only consider the assignment of the transmission power of each frame separately.

7 Introduction The authors derive a set of equations that correlate the transmission powers of RTS, CTS, DATA and ACK frames. The authors derive a class of adaptive power control algorithms (Core-PC).

8 Correlative Power Constraints -- Basic Framework and Definitions The transmission zone – The received power level of a frame from node i in its transmission zone is higher than or equal to κ. The carrier sensing zone – The received power level of a frame from node i in its carrier sensing zone is higher than or equal to η.

9 Correlative Power Constraints -- Noise Level Estimation When node A is receiving the CTS reply from a node B, we assume – The channel at node A is idle. – The node’s NAV is always set and the node is silenced whenever it is in the transmission zone. – The thermal noise level is negligible. – The propagation model is the two ray ground propagation model. Path loss

10 Correlative Power Constraints -- Noise Level Estimation R avg : average transmission range P avg : average transmission power Δ : the density of simultaneous transmitters outside A’s transmission zone Δ is upper bounded by

11 Correlative Power Constraints -- Noise Level Estimation According to the two ray ground propagation model

12 Correlative Power Constraints -- Requirements on Power Assignment for Frame Reception The received power of RTS from node A to node B at location B The received power of the CTS at node A must also fulfill the SIR requirement. SIR threshold The transmission power of CTS from node B to node A AB RTS CTS

13 Correlative Power Constraints -- Requirements on Power Assignment for Frame Reception AB

14 To simplify the notation,

15 Correlative Power Constraints -- Requirements on Power Assignment for Frame Reception

16 Correlative Power Constraints -- Feasibility of Power Assignment

17 The minimal possible power assignment for a DATA frame in a successful 4-way handshake is

18 Core-PC

19 In Algorithm 1, different combination of (P RTS,P avg ) lead to different power assignment algorithms.

20 Core-PC Three alternative approaches may be adopted for setting the P RTS. – (a) Simple scenario P RTS =P max – (b) Symmetric scenario P RTS =P CTS – (c) Minimum power scenario The RTS frame is transmitted at a power level such that the DATA transmission power is minimized.

21 Core-PC Similarly, there are different ways of choosing the value of P avg. – (A) Worst case scenario P avg =P max – (B) Node-related adaptive scenario (i) initially P avg =P max (ii) all other nodes transmit their DATA frame at the same power level – (C) Network-related adaptive scenario P avg =0.9P avg +0.1P t transmission power of a captured frame

22 Core-PC (a)(A)(b)(A)(c)(A)

23 Core-PC

24 Performance Evaluation Simulator: NS-2 Routes: AODV Data rate: 11Mbps κ: 3.652e-10 Watts η: 1.559e-11 Watts ζ: 10dB P max : 0.2818 Watts R max : 250m

25 Performance Evaluation -- Single Hop Scenario 50m (I) 200m (II) 150m CBR traffic is generated and carried in UDP datagrams with a packet size of 512 bytes Two packet sending rate: – 200 packets/s per sender – 400 packets/s per sender

26 Performance Evaluation -- Single Hop Scenario Rate = 200 PKT/SECEND200m

27 Performance Evaluation -- Single Hop Scenario Rate = 400 PKT/SECEND200m

28 Performance Evaluation -- Single Hop Scenario Rate = 400 PKT/SECEND150m

29 Performance Evaluation -- Multi-Hop Static Scenario 49 nodes 400*400 m 2 area 7 flows are set between randomly chosen end-to-end source-destination pairs Packet size is 512 bytes

30 Performance Evaluation -- Multi-Hop Static Scenario

31

32 Performance Evaluation -- Multi-Hop Scenario With Mobility 5 m/s

33 Performance Evaluation -- Multi-Hop Scenario With Mobility

34 Conclusion The correlations among the required transmission power of RTS/CTS/DATA/ACK – derived constraints that ensure the correct delivery Using these constraints – The authors developed a class of correlative power control algorithms Simulations have shown the algorithm achieves – Higher throughput – Lesser energy consumption

35 Thank you


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