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The research about power control in Our LAB

The research about power control in Our LAB

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The research about power control in Our LAB

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  1. The research about power control in Our LAB 2003, 07, 23

  2. Introduction • Single-Channel MAC Protocol with Busy Tones and Power Control (2000) • Multi-Channel MAC Protocol with Power Control (2001) • Increasing the Throughput of Packet Radio Networks with Power Adjustment (2001) • Power-Aware Routing for Energy Conserving and Balance in Ad Hoc Networks (2002) • Energy-Conserving Grid Routing Protocol in Mobile Ad Hoc Networks (2002)

  3. Single-Channel MAC Protocol with Busy Tones and Power Control 吳世琳 2000

  4. Goal • Contributions: • Increasing channel Utilization • Saving battery energy • Combining power control, RTS/CTS-basedand busy-tone-basedprotocols together

  5. Some important terms • Hidden-terminals • Exposed-terminals • Traffic load • Throughput • End-to-End Delay

  6. A B C D A B C

  7. Review of some MAC protocols • CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) • RTS/CTS-based protocols • RTS/CTS dialogue Enhanced with Busy Tones • A New MAC Protocol with Power Control

  8. CTS-2 CTS-1 RTS-2 RTS-1 CTS-2 CTS-1 CTS-1 RTS/CTS-based protocols D C E B A

  9. RTS/CTS dialogue Enhanced with Busy Tones • DBTMA (Dual busy Tone Multiple Access) • Single common channel is split into data and control channels • Narrow-band busy tone: • Transmit Busy Tone (BTt) and Receive Busy Tone (BTr) BTt BTr Control channel Data channel Frequency

  10. RTS/CTS dialogue Enhanced with Busy Tones • BTt : a host is transmitting • BTr :a host is receiving • A sending host must turn BTt on when transmitting data packets • A receiving host must turn BTr on when it replies a CTS • A host wants to send a RTS: check BTr • A host want to reply a CTS: check BTt

  11. CTS-2 +BTr CTS-1 +BTr RTS-2 RTS-1 CTS-2 +BTr CTS-1 +BTr CTS-1 +BTr RTS/CTS dialogue Enhanced with Busy Tones D C E B A

  12. D D C C E E B A B A F F A New MAC Protocol with Power Control

  13. A New MAC Protocol with Power Control • To use the exchange of RTS/CTS packets to determine power level • Power levels: • Pmax : the maximum transmission power • Pmin : the minimum power level • Pnoise : a power level regarding a signal as a noise

  14. A New MAC Protocol with Power Control • Transmission Power • Signal Strength • Tuning Power Levels: • Pr = Pt (  / 4d )n gt gr • Pmin = PCTS (  / 4d )n gt gr • Pmin / Pt = PCTS / Pr • : carrier wavelength, d: distance, g :antenna gains

  15. A New MAC Protocol with Power Control • HostX intends to send a RTS to HostY use power level PX • If no receiving any busy tone, then PX = Pmax • Otherwirse, PX = Pmax * Pnoise / Pr (Pr is the power level of the highest power among all BTr) • HostY receives HostX’s RTS • If there is any busy tone, Then HostY ignore RTS • Otherwise, HostY replies CTR with Pmax and turn on BTr at Pmax

  16. A New MAC Protocol with Power Control • When HostX receives CTS, • turning on BTt and transmitting data packets • PX = Pmin * Pmax / Pr (Pr is the power level of CTS)

  17. P.S. • Performance Analysis (read by yourself) • Simulation results (read by yourself)

  18. Multi-Channel MAC Protocol with Power Control 吳世琳 2001

  19. Multi-channel MAC Protocols • Channel assignment • Assigning channel to user • Medium access • Resolving the contention/collision problems

  20. DCA-PC (Dynamic Channel Assignment with Power Control) • Feature • Dynamically channel assignment (RTS/CTS/RES) • Independent of the network size, topology, and degree • Clock synchronization is not necessary • Channel model • One control channel • N data channels D1, D2, D3, …, Dn

  21. DCA-PC (Dynamic Channel Assignment with Power Control) • Hosts is equipped with two half-duplex transceiver • Control transceiver • Data transceiver • Data structures • CUL[i]: Channel Usage List • POWER[i]: the power level using to send

  22. DCA-PC (Dynamic Channel Assignment with Power Control) D A C F B E

  23. Increasing the Throughput of Packet Radio Networks with Power Adjustment 黃啟富 2001

  24. PRN (Packet Radio Networks)

  25. Simple simulation result

  26. Solution for SAPA – distance-based scheme • Each host has a common power (Pi) and a code (ci) • Increasing the powers of individual stations to increase the network connectivity • Under the constraint, that no primary and secondary collision should occur

  27. Solution for SAPA – distance-based scheme • L: the list of all station pairs (i,j) • Link (i,j)  G and (dist(i,j)) • Sort L in an ascending order of the distance • Collision array (col [i ]): the set of codes used by the host and it’s neighbors • col [i ] = {ci}  { cj | (i,j)  G }

  28. Solution for SAPA – distance-based scheme • Pick 1st entry (i,j) of L •  k : -1 (Pi) < dist(i,k)  dist(i,j)  ci col [k] •  k : -1 (Pj) < dist(j,k)  dist(i,j)  ci col [k] • Both condition hold, adding link (i,j) will no suffer from primary and secondary collision • If so, changing the power setting and update collision array • Remove (i,j) from L and if L is not empty goto step 3

  29. Solution for SAPA – distance-based scheme Original Link F2 Bidirectional Link H4 Unidirectional Link E2 G3 C1 A3 D1 B5

  30. Power-Aware Routing for Energy Conserving and Balance in Ad Hoc Networks 賴正偉 2002

  31. Goal • Reducing power consumption in transmission • A route consists of larger remaining energy hosts and accumulatively consumes less transmission power is considered as a better one

  32. Choose a suitable transmission power

  33. A A H Ptk-1 H Ptk H H Region K Region K Change transmission power

  34. Cost Function • Bi(0): the initial energy of hosti • Bi(t): the remaining energy of hostj at time t • Rbi : remaining energy ratio • Pij : the transmission power used by hosti to send packets to hostj • Ri(t) : remaining transmission time

  35. Cost Function • Cost = x Pij

  36. PCSR – route discovery B(0.8) D(0.7) source A(0.9) destination C(0.9) F(0.8) E(0.6)

  37. PCSR – route discovery B(0.8) D(0.7) (0,0.9,-1,”A”) A(0.9) C(0.9) F(0.8) HostA broadcast route request packet E(0.6)

  38. PCSR – route discovery • Assume Pt1 is 0.3 W, Pt2 is 0.2 W, Pt3 is 0.1 W • All hosts have initial energy 100 W 0.2/0.9 90/0.2 B(0.8) (0.22,0.8,450,”A,B”) Pt2 D(0.7) A(0.9) C(0.9) F(0.8) HostB broadcast route request packet E(0.6)

  39. PCSR – route discovery B(0.8) D(0.7) A(0.9) Pt1 (0.33,0.9,300,“A,C”) C(0.9) F(0.8) E(0.6) HostC broadcast route request packet

  40. PCSR – route discovery B(0.8) Pt2 D(0.7) (0.47,0.7,400,“A,B,D”) A(0.9) 0.22+0.25 C(0.9) F(0.8) E(0.6) HostD broadcast route request packet sent by HostB

  41. PCSR – route discovery B(0.8) D(0.7) A(0.9) (0.44,0.7,300.“A,C,D”) Pt3 C(0.9) F(0.8) E(0.6) HostD broadcast route request packet sent by HostC

  42. PCSR – route discovery B(0.8) D(0.7) A(0.9) Pt3 C(0.9) F(0.8) E(0.6) (0.44,0.6,300,“A,C,E”) HostE broadcast route request packet

  43. PCSR – route discovery B(0.8) (0,22,0.8,450,”A,B”) (0,0.9,-1,”A”) D(0.7) (0.47,0.7,400,“A,B,D”) A(0.9) Pt3 (0.61,0.8,400,“A,B,D,F”) C(0.9) F(0.8) E(0.6) HostF receives the first route request packet and then wait until Wreq elapsed

  44. PCSR – route discovery B(0.8) D(0.7) (0.33,0.9,300,“A,C”) (0.44,0.7,300,“A,C,D”) A(0.9) Pt3 (0,0.9,-1,”A”) (0.58,0.8,300,“A,C,D,F”) C(0.9) F(0.8) E(0.6) HostF receives the second route request packet

  45. PCSR – route discovery B(0.8) D(0.7) A(0.9) (0.60,0.8, 300,“A,C,E,F”) (0,0.9,-1,”A”) Pt3 C(0.9) F(0.8) (0.33,0.9,300,“A,C”) E(0.6) (0.44,0.6,300,“A,C,E”) HostF receives the third route request packet

  46. PCSR – route discovery B(0.8) D(0.7) A(0.9) C(0.9) F(0.8) E(0.6) (0.60,0.8, 300,“A,C,E,F”) HostA receives route reply packet and starts to send packets to HostF

  47. Energy-Conserving Grid Routing Protocol in Mobile Ad Hoc Networks 胡政達 2002

  48. Goal • Our motivation is to design a energy-conserving routing protocol • Reduce the hosts’ energy consumption when idle • Prolong the lifetime of whole network • Maintain good packets delivery quality

  49. Power consumption • Power consumption of Lucent IEEE 802.11 WaveLan card • A mobile host still consumes much energy even when idle

  50. Geography-informed energy conservation for ad hoc routing (GAF) • The geographic area is partitioned into grids • In a grid, one mobile host is active and others can sleep • A host will set the sleeping duration before if goes to sleep • After this period of sleep, the host will wake up to check its activity • No way to ensure that a destination host is active when packets are sent to it