Current Issue : October - December Volume : 2016 Issue Number : 4 Articles : 5 Articles
With apparent advantages of severalGHz license-free spectra, low power consumption, low-cost implementation ofCMOS devices,\nand so forth, 60GHz wireless communication technology becomes the first choice for short-range high ratewireless communication\nin future wireless personal area network (WPAN) and wireless local area network (WLAN).While different from commonWPAN\nsystem with omnidirectional communication, 60GHz-WPAN system generally adopts directional communication. In this paper,\na device (DEV) interconnected mechanism of 60GHz-WPAN based on switched beamforming technology is structured firstly.\nWithout considering the directional transmission characteristic of 60GHz communication, most of the 60GHz-WPAN Medium\nAccess Control (MAC) protocols fail to make full use of the high spatial reuse degree caused by directional communication.\nIn this paper, an average time slot multiplexing allocation (ATSMA) algorithm based on space/time division multiple access\n(STDMA) solution is proposed, which allows concurrent transmission in a single time slot. The designed link schedule process\nincludes common channel interference (CCI) probing scheme, link coexistence determination scheme, and link schedule algorithm.\nExtensive simulations are conducted in order to demonstrate the efficiency of proposed scheme. Simulation results demonstrated\nthat the capacity gain is obvious using ATSMA algorithm, no matter whether under omnidirectional antenna or under directional\nantenna....
In this paper, we promote the packet function (e.g., packet size) -aware extension of the Dijkstra algorithm (i.e.,\nPFA_SPF) as a base algorithm where any routing protocol can evolve it and integrate it with appropriate routing\nmetrics. In particular, we propose a generic algorithm for packet function-aware path setup for multi-hop networks.\nThe algorithm is based on a generic and novel extension of the classical Dijkstra algorithm in which the cost of each\nlink is a non-negative-valued function of packet parameter(s) (e.g., packet size) rather than a scalar value. The\nalgorithm minimizes the sum of the cost functions (e.g., total transmission delay or total energy consumption)\nexperienced by each packet (e.g., maximizing the throughput) from the source to the destination node. We did initial\nanalysis based on simulation of the algorithm for various random multi-hop wireless networks (e.g., 802.11), utilizing\nrealistic link delay models. Finally, we demonstrate the initial significant potential performance improvements of our\nalgorithm over the existing prior art....
Indoor localization in wireless sensor networks (WSN) is a challenging process. This paper proposes a new approach\nto solve the localization problematic. A fuzzy linguistic localization scheme is proposed. Based on interval type 2\nfuzzy logic (IT2FL), a signal processing of the radio signal strength indicator (RSSI) minimizes the uncertainty in RSSI\nmeasurements from anchors caused by the indoor obstacles. The fuzzy system subdivides the map on fuzzy sets\ndescribed by a new fuzzy location indicator (FLI). Fluctuations on RSS fingerprints are then reduced thanks to the\nIT2FL in the input side and the FLI in the output side. Experimentations were done in the Cynapsys indoor environment\non a WSN test bed. The experimental results prove higher success rate in position estimations thanks to the FLI concept\nand the superiority of interval type 2 fuzzy logic to handle signal fluctuations...
In this paper, we investigate the channel estimation and time synchronization problem based on the zero correlation\nzone (ZCZ) sequence set for single carrier multiple-input multiple-output frequency domain equalization (SC-MIMOFDE).\nA factorized construction of ZCZ sequence set considering the properties of both ZCZ and nonzero correlation\nzone (NCZ) is proposed with efficient generator and correlator, which can be in favor of timing synchronization and\nchannel estimation both in performance and computation complexity. Using the ZCZ sequence set, a new algorithm\ncalled twice section-maximum algorithm is put forward to eliminate energy interference among channels from\ndifferent transmitting antennas to the same receiving antenna. The performance achieved by the developed\nalgorithm which performs joint timing synchronization and channel estimation with lower computational cost is\nbetter than that of the conventional method....
Cognitive radio networks (CRN), in their quest to become the preferred next-generation wireless communication\nparadigm, will depend heavily on their ability to efficiently manage the limited resources at their disposal in meeting\nthe demands of their numerous users and driving their operations. As a result, a considerable amount of research\nwork has been recently dedicated to investigating and developing resource allocation (RA) models that capture the\nessentials of CRN. The various ideas put forward by researchers to address RA problems in CRN have been somewhat\ndiverse, and somehow, there seem to be no links that bring cohesion and clarity of purpose and ideas. To address this\nproblem and bridge the gap, in this paper, a comprehensive study on the prevalent techniques developed for\naddressing RA problems in CRN is carried out, with an intent to put some structure, relevance and meaning to the\nvarious solution approaches. The solution models are therefore grouped and/or classified based on certain\noutstanding criteria, and their strengths and weaknesses highlighted. Open-ended problems are identified, and\nsuggestions for improving solution models are given. The study therefore gives good directions for further\ninvestigations on developing RA solutions in CRN....
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