Integrated Coverage and Connectivity Configuration in Wireless Sensor Networks Xiaorui Wang, Guoliang Xing, Yuanfang Zhang*, Chenyang Lu, Robert Pless, Christopher Gill Department of Computer Science and Engineering Washington University SENSYS 2003 Chun-wei

Outline Introduction Coverage and connectivity configuration when R c ≥ 2R s Coverage Configuration Protocol (CCP) Coverage and connectivity configuration when Rc < 2Rs SPAN+CCP Simulation Conclusion

Introduction Energy is a paramount concern in wireless sensor network  Applications need to operate for a lone time An effective approach for energy conservation  Schedule maximize number of extraneous nodes to sleep  Remain active nodes provide continue service  Active nodes must maintain Sensing coverage Network connectivity

Introduction Present the novel protocols  Dynamically configure a sensor network  Guarantee degree of coverage  Network connectivity

Coverage and connectivity configuration when R c ≥ 2R s Theorem : For a set of sensors that at least 1- cover a region A, the communication graph is connected if R c ≥ 2R s A B Rs

Coverage and connectivity configuration when R c ≥ 2R s Theorem : For a set of sensors that at least 1- cover a region A, the communication graph is connected if R c ≥ 2R s A B Rs Rc

Coverage and connectivity configuration when R c ≥ 2R s Under the condition that R c ≥ 2R s  A sensor network only needs to be configured to guarantee coverage in order to satisfy both coverage and connectivity We present a new Coverage Configuration Protocol (CCP)  Decentralize protocol  Configure a sensor network  Guarantee degree of coverage

Coverage Configuration Protocol (CCP) Each node executes an eligibility algorithm to determine whether it is necessary to become active  K s -Coverage Eligibility Algorithm ineligibility actived

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Define : Sensing region v

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Define : Sensing region v V’s sensing circle

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Define : Sensing region v Sensing Region Not include v’s sensing circle

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Define : Sensing region Intersection points v Sensing Region Not include v’s sensing circle vu

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Define : Sensing region Intersection points v Sensing Region Not include v’s sensing circle vu A v

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Define : Sensing region Intersection points v Sensing Region Not include v’s sensing circle vu A v

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Theorem : A region A is K s -covered if all intersection points are at least K s -covered The set of sensing circles partition A into a collection of coverage patches  All points in the coverage patches have the same degree of coverage A

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Theorem : A region A is K s -covered if all intersection points are at least K s -covered S The coverage patch S is < K s -covered

Coverage Configuration Protocol (CCP) - Ks-Coverage Eligibility Algorithm Theorem : A convex region A is K s -covered if all intersection points are at least K s -covered S The intersection points have the same degree of coverage as S

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Theorem : A convex region A is K s -covered if all intersection points are at least K s -covered S A x u v w The coverage patch S is < K s -covered

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Theorem : A convex region A is K s -covered if all intersection points are at least K s -covered S A x u v w The intersection points have the same degree of coverage as S

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm We can transform the problem of determining the coverage degree of region to the intersection point Each sensor finds whether all intersection points in its sensing region are at least K s - covered  If all intersection points are at least K s -covered Ineligible for turning active  If one of the intersection points is < K s -covered Eligible for turning active

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm V

V

V All intersection points in V’s sensing region are at least K s -covered

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm Find all intersection points  Each node needs to consider all sensors in its sensing neighbor  Each node broadcast the HELLO message periodically Location and status information V u |uv|≤2R s

Coverage Configuration Protocol (CCP) - K s -Coverage Eligibility Algorithm In CCP, each node determines its eligibility using K s -coverage eligibility algorithm  Each node may switch state dynamically when its eligibility change A node can be in one of three states :  SLEEP  LISTEN  ACTIVE

Coverage Configuration Protocol (CCP) - switch state In SLEEP : Sleep time (T S ) T S expire t Listen time

Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message JOIN A B C D E F

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message Evaluate its eligibility Ineligible A B C D E F

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message Evaluate its eligibility Ineligible Return to sleep state Sleep time (T S ) A B C D E F

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F withdraw

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F withdraw Evaluate its eligibility eligible Join timer

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F Evaluate its eligibility Join timer eligible Receive JOIN message G JOIN

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F Evaluate its eligibility Join timer eligible Receive JOIN message G Evaluate its eligibility ineligible LISTEN time expire Sleep time (T S )

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F Evaluate its eligibility Join timer eligible Receive JOIN message G Evaluate its eligibility ineligible LISTEN time expire Sleep time (T S )

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F Evaluate its eligibility Join timer eligible G T J expire

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F Evaluate its eligibility Join timer eligible G Broadcast a Join message T J expire

Listen time Coverage Configuration Protocol (CCP) - switch state In LISTEN : t Receive HELLO, WITHDRAW, or JOIN message A B C D E F Evaluate its eligibility Join timer eligible G Broadcast a Join message T J expire Active State

Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Active State Update Sensing Neighbors Evaluate its eligibility Receive HELLO message eligible Remain Active state

Active Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Update Sensing Neighbors Evaluate its eligibility Receive HELLO message ineligible Withdraw Timer A B C D E F G Hello T W expire

Active Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Update Sensing Neighbors Evaluate its eligibility Receive HELLO message ineligible Withdraw Timer A B C D E F G Broadcast a WITHDRAW message T W expire

Active Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Update Sensing Neighbors Evaluate its eligibility Receive HELLO message ineligible Withdraw Timer A B C D E F G Broadcast a WITHDRAW message T W expire Sleep time (T S )

Active Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Update Sensing Neighbors Evaluate its eligibility Receive HELLO message ineligible Withdraw Timer A B C D E F G Hello

Active Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Update Sensing Neighbors Evaluate its eligibility Receive HELLO message ineligible Withdraw Timer A B C D E F G withdraw Receive HELLO, or WITHDRAW message

Active Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Update Sensing Neighbors Evaluate its eligibility Receive HELLO message ineligible Withdraw Timer A B C D E F G Evaluate its eligibility Receive HELLO, or WITHDRAW message eligible

Active Coverage Configuration Protocol (CCP) - switch state In ACTIVE : t Update Sensing Neighbors Evaluate its eligibility Receive HELLO message ineligible Withdraw Timer A B C D E F G Evaluate its eligibility Receive HELLO, or WITHDRAW message eligible Cancel T W

Coverage and connectivity configuration when R c < 2R s CCP cannot guarantee connectivity if R c < 2R s Integrate CCP with an existing connectivity maintain protocol  Provide both sensing coverage and communication connectivity A RsRs B RcRc

SPAN+CCP “ Span: An Energy-Efficient Coordination Algorithm for Topology Maintenance in Ad Hoc Wireless Networks “ Mobicom’03  Maintain a communication backbone composed of active node (=coordinator)  The communication backbone maintains the topology of the network All active nodes are connected through the backbone All inactive nodes are directly connected to at least one active node

SPAN+CCP Coordinator eligibility rule  Two of its neighbors cannot reach each other either directly or via one or two coordinator A B C D X E

SPAN+CCP Coordinator eligibility rule  Two of its neighbors cannot reach each other either directly or via one or two coordinator B C D E A X

SPAN+CCP Coordinator eligibility rule  Two of its neighbors cannot reach each other either directly or via one or two coordinator B C D E A X

SPAN+CCP Coordinator eligibility rule  Two of its neighbors cannot reach each other either directly or via one or two coordinator B C D E A Coordinator eligibility

SPAN+CCP Integrating CCP with SPAN Eligibility algorithm for providing both coverage and connectivity  Eligibility rule for inactive node : According to the eligibility rule of SPAN or CCP to become active  Eligibility rule for active nodes An active node will withdraw if it satisfies the Eligibility rule of neither SPAN nor CCP

Simulation NS-2 simulator 400×400 m 2 coverage region 160 nodes are randomly distributed in the field Sensing range 50m The requested coverage degree K S = 1

Simulation R C /R S = 1.5 Sink Active node Inactive node

Simulation R C /R S = 1.5

Simulation

Conclusion Present CCP  achieve different degrees of coverage requested by applications Integrate CCP with SPAN  provide both coverage and connectivity guarantees

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