Efficient Broadcast in Wireless Ad Hoc and Sensor Networks with a Realistic Physical Layer

摘要: Efficient Broadcast in Wireless Ad Hoc and Sensor Networks with a Realistic Physical Layer Hui Xu J.J. Garcia-Luna-Aceves Computer Engineering, University of California at Santa Cruz, CA, USA Email: { xuhui,jj } @soe.ucsc.edu Abstract— To minimize energy consumption efficient broadcast- ing ad hoc sensor networks aims to select small sets forwarding nodes the transmission radius. However, physical-layer characteristics radio links are such that chosen receivers which may not be able decode packets sent them, even without multiple access interference. We present an analytical model show radius used for can establish tradeoff between minimizing ensuring network coverage. then propose mechanism called redundant radii, involves using two form buffer zone guarantees availability logical physical network, one broadcast-tree calculation other actual data transmission. The effectiveness proposed scheme improving coverage is validated analytically by simulation. I. I NTRODUCTION Broadcasting indispensable operation wireless networks. It needed route discovery, infor- mation dissemination, publication services, gathering, task distribution, time synchronization, so on. Given untethered devices rely on batteries limited capacity, most important criteria when designing commu- nication protocols efficiency. Hence, key objec- tive broadcasting algorithms consumption. Tree-based broadcasts provide best efficiency, because they smallest number nodes. Because depends ranges, straightforward way preserve limit radii those distances reach selected neighboring while adaptation has been explored many schemes past, have assumed ideal physical- layer within given range receive probability 1. This, course, realistic practical situations. In reality, received power levels significant variations around mean probabilities smaller than As consequence, tree-based suffer from poor work presented this paper inspired recent research [1], [2], [3], [4]. Takai et al. [1] showed importance layer, though evaluated do directly interact layer. Stojmenovic [4] guidelines how design routing taking impact into consideration. They applied log normal shadow fading represent derive approximation p(d) receiving packet successfully as function distance d several localized case position destination known, optimizing expected hop count (for acknowledge- ment), or maximizing delivery (when no acknowledgements sent). considered aware under Finally, mentioned about concept dominating process. Section II presents some preliminaries system we assue our study, III showing ratio increased lengthening nodes; how- ever, attained also increasing each node. exists approximate computed general formula according required IV proposes “redundant radius” broadcasting, makes use calculation. After neighborhood information collected, calculate broadcast tree; longer based network. V addresses simulations. II. P RELIMINARIES AND S YSTEM M ODEL multipath effects [5] caused reflection, diffrac- tion scattering, signal level obtained receiver actually vector sum all signals incident any direction angle arrival. Some will aid direct path, subtract (or tend cancel) path. cause success reception statistic variable. above RF problems mitigated ways: design, antenna waveform building environment design. cannot avoided completely;