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EnergyEfficient Collision Resolution in Wireless AdHoc Networks
, 2003
"... In this paper, we address the collision resolution (CR) problem from an energyefficiency point of view and develop a residualenergybased collision resolution algorithm (CRA) for energylimited terminals. In this algorithm, which is based on treesplitting, packets involved in a collision are part ..."
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In this paper, we address the collision resolution (CR) problem from an energyefficiency point of view and develop a residualenergybased collision resolution algorithm (CRA) for energylimited terminals. In this algorithm, which is based on treesplitting, packets involved in a collision are partitioned into subsets according to the amount of residual battery energy left at the corresponding terminals, and retransmissions are scheduled according to a tree structure. We extend the proposed energybased CR approach to cases without hard energy constraints but, rather, with energyefficiency objectives. The algorithm then utilizes the distance from the receiver as the criterion. We evaluate the proposed algorithm via simulation for communication systems ranging from simple singlecell classical collision channel models to general multihop wireless adhoc networks.
An analytic approach to the asymptotic variance of trie statistics and related structures
, 2013
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Analysis of dynamic tree algorithms
 In preparation
, 2004
"... Abstract. In this paper, a general tree algorithm processing a random flow of arrivals is analyzed. CapetanakisTsybakovMikhailov’s protocol in the context of communication networks with random access is an example of such an algorithm. In computer science, this corresponds to a trie structure with ..."
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Abstract. In this paper, a general tree algorithm processing a random flow of arrivals is analyzed. CapetanakisTsybakovMikhailov’s protocol in the context of communication networks with random access is an example of such an algorithm. In computer science, this corresponds to a trie structure with a dynamic input. Mathematically, it is related to a stopped branching process with exogeneous arrivals (immigration). Under quite general assumptions on the distribution of the number of arrivals and on the branching procedure, it is shown that there exists a positive constant λc so that if the arrival rate is smaller than λc, then the algorithm is stable under the flow of requests, i.e. that the total size of an associated tree is integrable. At the same time a gap in the earlier proofs of stability of the literature is fixed. When the arrivals are Poisson, an explicit characterization of λc is given. Under the stability condition, the asymptotic behavior of the average size of a tree starting with a large number of individuals is analyzed. The results are obtained with the help of a probabilistic rewriting of the functional equations describing the dynamic
TABLE I PARAMETERS USED IN THIS PAPER
"... Abstract—In radio frequency identifications (RFIDs), an idle slot can be interrupted by the reader and takes less time than the other slots. In this case, the widely used binary splitting (BS) protocol is not optimal. Mary splitting (M> 2) with a carefully selected M outperforms BS, because it c ..."
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Abstract—In radio frequency identifications (RFIDs), an idle slot can be interrupted by the reader and takes less time than the other slots. In this case, the widely used binary splitting (BS) protocol is not optimal. Mary splitting (M> 2) with a carefully selected M outperforms BS, because it can take into account smaller duration of the idle slots. In this paper, we provide optimal value of M (M) for varying slot sizes that yields minimum identification time. The proposed scheme is called optimal splitting (OS). We also revise OS to deal with mobile tags and propose the optimal splitting with arrival tags blocking (OSATB) protocol. Extensive simulations show that OS and OSATB consistently yield better performance than the other splitting and treebased schemes. Note to Practitioners — An RFID reader can interrupt the slot in which no tags reply for a predefined time interval, resulting in an short idle slot. In this case, binary splitting is not the best choice but simple increase of the splitting level can yield much better performance. Since the slot sizes are usually fixed for a given system, the optimum value can be calculated offline without introducing extra computation complexity during the realtime identification. Index Terms—Mobile tags, optimal splitting, radio frequency identification (RFID), splitting algorithms, tag anticollision. I.
Error Resilient Estimation and Adaptive Binary Selection for Fast and Reliable Identification of RFID Tags in ErrorProne Channel
"... Abstract—In RFID systems, far field passive tags send information using back scattering. The signal level is typically very small, so channel error during transmission may occur frequently. Due to channel error, performance of RFID tag identification under errorprone channel is degraded compared to ..."
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Abstract—In RFID systems, far field passive tags send information using back scattering. The signal level is typically very small, so channel error during transmission may occur frequently. Due to channel error, performance of RFID tag identification under errorprone channel is degraded compared to that under errorfree channel. In this paper, we propose a novel error resilient estimation and adaptive binary selection to overcome the problem of channel errors. Our proposed error resilient estimation algorithm can estimate the number of tags and the channel state accurately regardless of frame errors. And our proposed adaptive binary selection reduces the idle slots caused by frame errors. Performance analysis and simulation results show that the proposed algorithm consumes up to 20 percent less time slots than the binary tree protocol and dynamic framed slotted ALOHA (DFSA) in various packet error rate (PER) conditions. Index Terms—Anticollision, channel error, collision resolution, RFID, tag estimation. Ç 1
THROUGHPUT OF QARY SPLITTING ALGORITHMS FOR
"... Abstract. The throughput characteristics of contentionbased random access channels which use Qary splitting algorithms (where Q is the number of groups into which colliding users are split) are analyzed. The algorithms considered are of the CapetanakisTsybakovMikhailovVvedenskaya (CTMV) type an ..."
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Abstract. The throughput characteristics of contentionbased random access channels which use Qary splitting algorithms (where Q is the number of groups into which colliding users are split) are analyzed. The algorithms considered are of the CapetanakisTsybakovMikhailovVvedenskaya (CTMV) type and are studied for infinite populations of identical users generating packets according to a discrete time batch Markovian arrival process (DBMAP). DBMAPs are a class of tractable Markovian arrival processes, which, in general, are nonrenewal. Free channelaccess is assumed in combination with Qary collision resolution algorithms that exploit either binary or ternary feedback. For the resulting schemes, tree structured QuasiBirthDeath (QBD) Markov chains are constructed and their stability is determined. The maximum achievable throughput is determined for a variety of arrival processes and splitting factors Q. It is concluded that binary (Q =2)andternary(Q =3) algorithms should be preferred above other splitting factors Q as the throughput for Q>3quickly degrades when subject to bursty arrival streams. If packets arrivals are correlated and bursty, higher throughput rates can be achieved by making use of biased coins.
Modeling of Cable Access Networks
, 2002
"... In the pelican project, several mathematical models have been developed that are relevant to the performance analysis of cable networks. The aim of this report is to give a short overview over some of these models. We consider a tandem model with a gate, a machine repair model with a gate, a multitr ..."
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In the pelican project, several mathematical models have been developed that are relevant to the performance analysis of cable networks. The aim of this report is to give a short overview over some of these models. We consider a tandem model with a gate, a machine repair model with a gate, a multitree model, and a Markovian tandem in which service intensities depend on the state of the system.
Efficient LTE Access with Collision Resolution for Massive M2M Communications
"... Abstract—LTE random access procedure performs satisfactorily in case of asynchronous, uncorrelated traffic arrivals. However, when the arrivals are correlated and arrive synchronously, the performance of the random access channel (RACH) is drastically reduced, causing a large number of devices to ..."
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Abstract—LTE random access procedure performs satisfactorily in case of asynchronous, uncorrelated traffic arrivals. However, when the arrivals are correlated and arrive synchronously, the performance of the random access channel (RACH) is drastically reduced, causing a large number of devices to experience outage. In this work we propose a LTE RACH scheme tailored for delaysensitive M2M services with synchronous traffic arrivals. The key idea is, upon detection of a RACH overload, to apply a collision resolution algorithm based on splitting trees. The solution is implemented on top of the existing LTE RACH mechanism, requiring only minor modifications of the protocol operation and not incurring any changes to the physical layer. The results are very promising, outperforming the related solutions by a wide margin. As an illustration, the proposed scheme can resolve 30k devices with an average of 5 preamble transmissions and delay of 1.2 seconds, under a realistic probability of transmissions error both in the downlink and in the uplink. I.