Design considerations in wireless sensor networks

We consider three problems in the design of wireless sensor networks: cross-layer optimization, neighbor discovery, and scheduling as a method of medium access control (MAC). Cross-layer optimization will be important for sensor networks, which typically have only one or two objectives to meet. We consider a sensor network which performs decentralized detection. We devise a method in which local observations by sensors are condensed into a single bit message and forwarded to a sink node which makes a final decision. The method involves unusual interactions between the application, the routing function, and the physical layer. Neighbor discovery is useful in sensor networks whose nodes are immobile, since routing and scheduling algorithms can make good use of neighbor information. We propose an asynchronous neighbor discovery algorithm. The algorithm is probabilistic: each node obtains a list of its neighbors which is possibly incomplete. Performance is analyzed and optimal paramete…

Author: Silverman, Nischom K

Source: University of Maryland

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Contents

Introduction
2 Cross-layer optimization in a wireless sensor network
2.1 Introduction
2.2 Network model
2.2.1 Data aggregation in model M1
2.2.2 Data aggregation in model M2
2.2.3 Routing
2.2.4 The link cost for M1
2.2.5 The link cost for M2
2.2.6 Taking account of finite energy
2.3 Simulation results
2.3.1 Comparing M1 to M2
2.3.2 Effect of unequal priors
2.3.3 Comparison of M1, M2, M3 and M4
2.3.4 Effect of network density
2.3.5 Summary of simulation results
2.4 Relation to a theoretical result
2.5 Conclusion
3 Wireless link scheduling with SINR constraints and power control
3.1 Introduction
3.2 Notation and definitions
3.3 The minimum length scheduling problem
3.3.1 LP formulation and hypergraphs
3.4 An algorithm to compute the min schedule length for superincreasing f
3.4.1 The algorithm for superincreasing f
3.4.2 Other tractable sub-cases
3.5 Complexity of the general SINR-constrained scheduling problem
3.6 A theorem on MAX-SINR-MATCHING
3.7 Finding maximal matchings
3.7.1 A heuristic for MAX-SINR-MATCHING
3.8 Conclusion
4 The feasibility of matchings in a wireless network
4.1 Introduction
4.2 Results on feasibility of matchings
4.3 Where all matchings are feasible
4.4 Appendix: Miscellaneous observations on the matrix A(L, π)
5 An asynchronous neighbor discovery algorithm for wireless sensor networks
5.1 Introduction
5.2 Problem statement
5.3 Algorithm description
5.4 Slotted analysis of A
5.5 Asynchronous analysis of A
5.5.1 Model
5.5.2 Performance of A
5.5.3 Robustness of A
5.6 Discussion
5.7 Conclusion
5.8 Appendix: Asynchronous analysis of E(h)
5.8.1 Regular hearings
5.8.2 Round-the-corner hearings
5.8.3 Optimal settings
5.9 Appendix: A distributed algorithm to commence neighbor discovery
5.9.1 Setting parameters for listen-only mode
Bibliography