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The continuous development of wireless networks and mobile devices has motivated an intense research in mobile data services. Some of these services provide the user with context-aware information. Specifically, location-based services and location-dependent queries have attracted a lot of interest. In this article, the existing literature in the field of location-dependent query processing is reviewed. The technological context (mobile computing) and support middleware (such as moving object databases and data stream technology) are described, location-based services and location-dependent queries are defined and classified, and different query processing approaches are reviewed and compared. Categories and Subject Descriptors: C.2.4 [Computer-Communication Networks]: Distributed Systems--Distributed applications; H.2.4 [Database Management]: Systems--Query processing; H.4.0 [Information Systems and Applications]: General General Terms: Algorithms, Design, Management Additional Key Words and Phrases: Continuous queries, location-based services, location-dependent data, location-dependent queries, mobile computing, query processing ACM Reference Format: Ilarri, S., Mena, E., and Illarramendi, A. 2010. Location-dependent query processing: Where we are and where we are heading. ACM Comput. Surv. 42, 3, Article 12 (March 2010), 73 pages. DOI = 10.1145/1670679.1670682, http://doi.acm.org/10.1145/1670679.1670682

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.comnet.2010.03.012 Byline: Preetha Thulasiraman, Xuemin (Sherman) Shen Keywords: Interference; Maximum concurrent flow; Spatial reuse; Power; Rate; Multihop cellular networks Abstract: This paper addresses the problem of interference aware resource allocation for OFDMA based hybrid hierarchical wireless networks. We develop two resource allocation algorithms considering the impact of wireless interference constraints using a weighted SINR conflict graph to quantify the interference among the various nodes: (1) interference aware routing using maximum concurrent flow optimization; and (2) rate adaptive joint subcarrier and power allocation algorithm under interference and QoS constraints. We exploit spatial reuse to allocate subcarriers in the network and show that an intelligent reuse of resources can improve throughput while mitigating interference. We provide a sub-optimal heuristic to solve the rate adaptive resource allocation problem. We demonstrate that aggressive spatial reuse and fine tuned-interference modeling garner advantages in terms of throughput, end-to-end delay and power distribution. Author Affiliation: Department of Electrical and Computer Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1 Article History: Received 15 October 2009; Revised 12 February 2010; Accepted 21 March 2010 Article Note: (footnote) [star] Parts of this paper have been presented at IEEE ICC 2009 and IEEE WiMesh 2009.