Showing papers in "IEEE Communications Letters in 2014"
TL;DR: This letter proposes a solid analytical formulation and analyzes the signal metrics (attenuation and propagation delay) for molecular communication via diffusion channel with an absorbing receiver in a 3-D environment and proposes a model and the formulation that match well with the simulations without any normalization.
Abstract: Within the domain of molecular communications, researchers mimic the techniques in nature to come up with alternative communication methods for collaborating nanomachines. This letter investigates the channel transfer function for molecular communications via diffusion. In nature, information-carrying molecules are generally absorbed by the target node via receptors. Using the concentration function, without considering the absorption process, as the channel transfer function implicitly assumes that the receiver node does not affect the system. In this letter, we propose a solid analytical formulation and analyze the signal metrics (attenuation and propagation delay) for molecular communication via diffusion channel with an absorbing receiver in a 3-D environment. The proposed model and the formulation match well with the simulations without any normalization.
354 citations
TL;DR: The evaluation shows that the new strategy can significantly reduce the number of required controllers, reduce the load of the maximum-load controller, and reduce the radius stretches compared with the K-center strategy with dynamic controller provision or dynamic scheduling.
Abstract: Controller placement is a key problem in software defined networks (SDNs). Previously, the solution to this problem only focused on propagation latency but ignored the load of controllers, which is a critical factor in real networks. In this letter, we define a capacitated controller placement problem (CCPP), taking into consideration the load of controllers, and introduce an efficient algorithm to solve the problem. The evaluation shows that the new strategy can significantly reduce the number of required controllers, reduce the load of the maximum-load controller, and reduce the radius stretches compared with the K-center strategy with dynamic controller provision or dynamic scheduling.
314 citations
TL;DR: It is shown that the proposed coordinated superposition coding (CSC) scheme can provide a reasonable transmission rate to a cell-edge user without degrading the rates to users near to BSs.
Abstract: In order to improve the spectral efficiency, non-orthogonal multiple access (NOMA) with superposition coding is employed in a coordinated system where downlink signals to users near to base stations (BSs) and cell-edge users are transmitted simultaneously. To support a cell-edge user in a NOMA channel, two coordinated BSs use Alamouti code. In order to see the performance, we derive expressions for the transmission rates to near and cell-edge users. It is shown that the proposed coordinated superposition coding (CSC) scheme can provide a reasonable transmission rate to a cell-edge user without degrading the rates to users near to BSs.
293 citations
TL;DR: A novel kind of punctured polar codes is proposed, which are constructed by certain constraints on both puncturing patterns and frozen sets such that the values of the punctured bits are known to the decoder.
Abstract: A novel kind of punctured polar codes is proposed in this paper The codes are constructed by certain constraints on both puncturing patterns and frozen sets such that the values of the punctured bits are known to the decoder As a result, the initialized log-likelihood ratios of the punctured bits can be set to infinity (or minus infinity), which guarantees a better decoding performance Furthermore, explicit puncturing patterns are designed for arbitrary code lengths The simulation results show that the proposed codes outperform the conventional punctured polar codes
217 citations
TL;DR: A new algorithm is proposed to construct polar codes, aimed at minimizing the exact BLER, instead of the upper bound of theBLER, and analysis indicates that the new method is less complex than the existing methods.
Abstract: Polar codes are usually constructed to minimize the upper bound of a block error ratio (BLER). In this paper, we discuss the estimation of the exact BLERs of polar codes as well as the construction of polar codes. Assuming that successive cancellation (SC) decoding is employed, we present a method for estimating the exact BLER of polar codes with the help of Gaussian approximation (GA). A new algorithm is proposed to construct polar codes, aimed at minimizing the exact BLER, instead of the upper bound of the BLER. Analysis indicates that the new method is less complex than the existing methods. It is also shown that the estimation results match the simulations well.
178 citations
TL;DR: A class of binary three-weight linear codes is constructed that has applications in authentication codes, secret sharing schemes, and association schemes, in addition to their applications in consumer electronics and communication and data storage systems.
Abstract: In this paper, a class of binary three-weight linear codes is constructed. Their dual codes are also studied. The dual codes are either optimal or almost optimal. These codes have applications in authentication codes, secret sharing schemes, and association schemes, in addition to their applications in consumer electronics and communication and data storage systems.
160 citations
TL;DR: Simulation results show that the proposed OB-MMSE detector provides similar performance to ML with near 80% reduction in complexity.
Abstract: Generalized spatial modulation (GSM), in which only part of the transmit antennas are activated in each time slot, was recently proposed as a trade-off between spatial modulation (SM) and vertical Bell laboratories space-time (V-BLAST). Although the maximum likelihood (ML) detector is able to achieve the optimal performance, its exhaustive search leads to intractable computational complexity. In this letter, an efficient signal detection algorithm, termed ordered block minimum mean-squared error (OB-MMSE), is proposed for achieving near-ML performance with low complexity. On one hand, an ordering algorithm is proposed to sort the possible transmit antenna combinations (TACs). On the other hand, the possible signal vector for each ordered TAC is detected by block-MMSE equalization. Simulation results show that the proposed OB-MMSE detector provides similar performance to ML with near 80% reduction in complexity.
147 citations
TL;DR: A new medium access control (MAC) enhancement to increase the uplink access efficiency and the success probability is improved by using the proposed algorithm through analysis and simulations.
Abstract: Machine-to-machine (M2M) communications is expected to be supported in the next-generation wireless LAN, IEEE 802.11ah. One of the most important issues for M2M communications is designing an effective medium access scheme to handle many devices. In this letter, we propose a new medium access control (MAC) enhancement to increase the uplink access efficiency. The proposed algorithm estimates the number of devices for the uplink access from the success probability. In the proposed algorithm, an access point (AP) determines the optimal size of the restricted access window (RAW) considering the relationship between the estimated number of devices and the size of RAW. We show that the success probability for the uplink access is improved by using our proposed algorithm through analysis and simulations.
124 citations
TL;DR: This paper investigates a multi-input single-output (MISO) wireless powered communication network (WPCN) under the protocol of harvest-then-transmit and proposes a robust algorithm to maximize the system throughput subject to the signal-to-noise ratio (SNR) outage probability constraints.
Abstract: This paper investigates a multi-input single-output (MISO) wireless powered communication network (WPCN) under the protocol of harvest-then-transmit. The power station (PS) with reliable power supply first replenishes the passive user nodes by radio-frequency wireless power transfer (WPT) in the downlink, then each user node transmits independent information to the sink by a time division multiple access (TDMA) scheme in the uplink. We consider the joint time allocation and beamforming design to maximize the system sum-throughput. With perfect channel station information (CSI) at the PS, a semi-closed form solution is proposed by exploiting the strict concavity of the joint design problem. Then, in the case with Gaussian CSI errors, a robust algorithm is proposed to maximize the system throughput subject to the signal-to-noise ratio (SNR) outage probability constraints. Simulation results demonstrate the efficiency of the proposed fast algorithm and validate the robust algorithm.
117 citations
TL;DR: A method for real-time detection of Denial-of-Service (DoS) attacks in IEEE 802.11p vehicular ad-hoc networks (VANETs) is proposed based on the "jamming" of periodic position messages exchanged by vehicles in a platoon.
Abstract: A method for real-time detection of Denial-of-Service (DoS) attacks in IEEE 802.11p vehicular ad-hoc networks (VANETs) is proposed. The study is focused on the "jamming" of periodic position messages (beacons) exchanged by vehicles in a platoon. Probabilities of attack detection and false alarm are estimated for two different attacker models.
117 citations
TL;DR: The approximate average symbol error rate of the considered beamforming and combining based hybrid AF cooperative scheme for M-ary phase shift keying constellation is derived; analytical diversity order of the hybrid system is obtained.
Abstract: In this paper, we consider the transmission of signals in a hybrid satellite-terrestrial cooperative system. In particular, we address the problem of beamforming and combining based amplify-and-forward (AF) relaying in a hybrid satellite-terrestrial cooperative system. In this set-up, a multiple antenna based relay node forwards the received satellite signals to the destination, by using a beamforming vector, and multiple antenna based destination node uses maximal ratio combining. The approximate average symbol error rate of the considered beamforming and combining based hybrid AF cooperative scheme for M-ary phase shift keying constellation is derived; analytical diversity order of the hybrid system is also obtained. Moreover, diversity calculations for some specific antenna configurations are shown for providing useful insight of the proposed scheme, at high signal-to-noise ratio.
TL;DR: This work presents a low complexity method for matching D2D links with cellular user equipments (CUEs) to form partners for spectrum sharing and presents a simple pairing algorithm to reduce the computational cost well below the well known Hungarian algorithm used in the literature for the pairing problem.
Abstract: Device-to-device (D2D) communications has attracted substantial research attention recently owing to its simplicity and its potential to improve spectrum and energy efficiency within the existing cellular infrastructure. This work presents a low complexity method for matching D2D links with cellular user equipments (CUEs) to form partners for spectrum sharing. The overall objective is to maximize well defined performance metrics of all D2D links and CUEs after successful pairing under power and QoS constraints. We begin by identifying a set of D2D link candidates for each CUE uplink for a requisite SINR level to reduce the number of potential pairing searches. More importantly, we present a simple pairing algorithm to reduce the computational cost well below the well known Hungarian (Kuhn-Munkres) algorithm used in the literature for the pairing problem. Our new algorithm exhibits low complexity and is effective in improving the sum rate of all spectrum sharing CUEs and D2D links with modest performance loss.
TL;DR: This paper derives approximate closed-form expressions of the probability density function and cumulative distribution function of the received signal-to-noise ratio of the MRC based receiver in SR fading LMS channels.
Abstract: In this paper, the maximal ratio combining (MRC) scheme in Shadowed-Rician (SR) fading land mobile satellite (LMS) channels is studied. The MRC scheme for SR fading LMS channels has been studied in existing literature; however, most of the existing analytical results are in the form of infinite power series, which are not in closed-form. In this paper, we derive approximate closed-form expressions of the probability density function and cumulative distribution function of the received signal-to-noise ratio of the MRC based receiver in SR fading LMS channels. Then we provide approximate closed-form expressions of the bit error rate (BER), outage probability, and capacity of the considered scheme. One of the derived closed-form BER expressions is found useful for obtaining the analytical diversity order and coding gain of the considered MRC scheme.
TL;DR: A novel Name Lookup engine with Adaptive Prefix Bloom filter (NLAPB) is conceived, in which each NDN name/prefix is split into B-prefix followed by T-suffix, and experimental results show that NLAPB is able to lower the false positive rate with respect to a lookup entirely based on Bloom filters.
Abstract: In Named Data Networking (NDN), packet forwarding decisions rely upon lookup operations on variable-length hierarchical names instead of fixed-length host addresses. This pivotal feature introduces new challenges in the deployment of NDN at the Internet scale. In this letter, a novel Name Lookup engine with Adaptive Prefix Bloom filter (NLAPB) is conceived, in which each NDN name/prefix is split into B-prefix followed by T-suffix. B-prefix is matched by Bloom filters whereas T-suffix is processed by the small-scale trie. The length of B-prefixes (and T-suffixes) is dynamically throttled based on their popularity in order to accelerate the lookup. Experimental results show that: (i) NLAPB is able to lower the false positive rate with respect to a lookup entirely based on Bloom filters; (ii) it decreases the memory requirements with respect to a trie-based approach; (iii) it reduces processing time with respect to both them.
TL;DR: Experimental results show that the proposed variation of Lyapunov exponent outperforms entropy-based method while reflecting relationship between source IPs and destination IPs, which is enabled by the possibility of combining their entropies.
Abstract: Distributed denial-of-service (DDoS) flooding attacks are still great threat to the network security, although methodologies and tools have been implemented to combat this problem. In this paper, a variation of Lyapunov exponent is proposed to detect anomalies in network traffic, based on entropy. Experimental results show that our approach outperforms entropy-based method while reflecting relationship between source IPs and destination IPs, which is enabled by the possibility of combining their entropies.
TL;DR: A novel Reinforcement Learning (RL)-based HAS client that dynamically adapts its behaviour by interacting with the environment to optimize the Quality of Experience (QoE), the quality as perceived by the end-user.
Abstract: HTTP Adaptive Streaming (HAS) is becoming the de facto standard for Over-The-Top (OTT)-based video streaming services such as YouTube and Netflix. By splitting a video into multiple segments of a couple of seconds and encoding each of these at multiple quality levels, HAS allows a video client to dynamically adapt the requested quality during the playout to react to network changes. However, state-of-the-art quality selection heuristics are deterministic and tailored to specific network configurations. Therefore, they are unable to cope with a vast range of highly dynamic network settings. In this letter, a novel Reinforcement Learning (RL)-based HAS client is presented and evaluated. The self-learning HAS client dynamically adapts its behaviour by interacting with the environment to optimize the Quality of Experience (QoE), the quality as perceived by the end-user. The proposed client has been thoroughly evaluated using a network-based simulator and is shown to outperform traditional HAS clients by up to 13% in a mobile network environment.
TL;DR: This letter shows the equivalence of the recently proposed generalized frequency division multiplexing (GFDM) communications scheme with a finite discrete critically sampled Gabor expansion and transform with an efficient algorithm for calculation of specific GFDM receiver filters.
Abstract: This letter shows the equivalence of the recently proposed generalized frequency division multiplexing (GFDM) communications scheme with a finite discrete critically sampled Gabor expansion and transform. GFDM is described with the terminology of Gabor analysis and the Balian-Low theorem is applied to prove the non-existence of zero-forcing receivers for certain configurations, having strong impact on the system performance. An efficient algorithm for calculation of specific GFDM receiver filters is derived and numerical examples confirm the theoretical results.
TL;DR: New mathematical frameworks to the computation of coverage probability and average rate of cellular networks are introduced, by relying on a stochastic geometry abstraction modeling approach, and it is proved that coverage and rate can be compactly formulated as a twofold integral for arbitrary per-link power gains.
Abstract: In this letter, we introduce new mathematical frameworks to the computation of coverage probability and average rate of cellular networks, by relying on a stochastic geometry abstraction modeling approach. With the aid of the Gil-Pelaez inversion formula, we prove that coverage and rate can be compactly formulated as a twofold integral for arbitrary per-link power gains. In the interference-limited regime, single-integral expressions are obtained. As a case study, Gamma-distributed per-link power gains are investigated further, and approximated closed-form expressions for coverage and rate in the interference-limited regime are obtained, which shed light on the impact of channel parameters and physical-layer transmission schemes.
TL;DR: This letter investigates performance enhancement by the concept of multi-carrier index keying in orthogonal frequency division multiplexing (OFDM) systems using a tight closed-form approximation of the bit error rate (BER).
Abstract: This letter investigates performance enhancement by the concept of multi-carrier index keying in orthogonal frequency division multiplexing (OFDM) systems. For the performance evaluation, a tight closed-form approximation of the bit error rate (BER) is derived introducing the expression for the number of bit errors occurring in both the index domain and the complex domain, in the presence of both imperfect and perfect detection of active multi-carrier indices. The accuracy of the derived BER results for various cases are validated using simulations, which can provide accuracy within 1 dB at favorable channels.
TL;DR: A ratio approach is used to eliminate the transmitting power uncertainty, combined with a search method for path-loss exponent under certain constraints, linear least squares is utilized to determine the location of the source node.
Abstract: In this letter we present a novel method for source node localization using received signal strength in situations where path-loss model parameters are unknown. First, a ratio approach is used to eliminate the transmitting power uncertainty, then, combined with a search method for path-loss exponent under certain constraints, linear least squares is utilized to determine the location of the source node. Simulations are used to demonstrate the feasibility and suitability of the proposed method. The simulation results indicate that the method presented outperforms other off-the-shelf source node localization algorithms intended for use when path-loss model parameters are unknown.
TL;DR: This letter investigates the effect of cochannel interference (CCI) on a hybrid satellite-terrestrial cooperative relay network (HSTCN), where both the satellite-destination and satellite-relay links undergo the shadowed Rician fading, whereas the relay-destinations link follows the Rayleigh fading.
Abstract: This letter investigates the effect of cochannel interference (CCI) on a hybrid satellite–terrestrial cooperative relay network (HSTCN), where both the satellite–destination and satellite–relay links undergo the shadowed Rician fading, whereas the relay–destination link follows the Rayleigh fading. By assuming that decode-and-forward (DF) protocol is adopted at the terrestrial relay, and the destination is corrupted by multiple CCI, we first derive the analytical expression for the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR). Then, based on the Meijer-G functions, we present an approximated yet accurate method to evaluate the average symbol error rate (ASER) of the cooperative network. Moreover, the asymptotic ASER at high signal-to-noise ratio (SNR) with respect to diversity order and array gain are also given to gain further insights. Finally, numerical results are provided to demonstrate the validity of the performance analysis as well as the impact of CCI on the HSTCN.
TL;DR: An enhanced implementation of PIT called MaPIT is presented, based on the proposed Mapping Bloom filter, which is a modified data structure of Bloom filter to satisfy the current network requirements and minimize the on-chip memory consumption.
Abstract: Named Data Networking (NDN) is a recent paradigm conceived for future Internet architectures, where communications are driven by contents instead of host addresses. To realize this paradigm, a novel data structure for forwarding processes, namely Pending Interest Table (PIT), is utilized in NDN node. Designing and evaluating a quick enough PIT with high capacity is a major challenge within the overall NDN research area. In this letter, based on our proposed Mapping Bloom filter, which is a modified data structure of Bloom filter, we present an enhanced implementation of PIT called MaPIT. Our evaluations indicate that MaPIT can minimize the on-chip memory consumption to 2.097 MB. And the probability of false positive is under 1% for 2 million names. It allows MaPIT to use SRAM as on-chip memory and satisfy the current network requirements.
TL;DR: A novel concept of security region is defined to intuitively illustrate the security from a spatial perspective of the physical-layer security of a multi-antenna transmission system in the presence of Poisson distributed eavesdroppers.
Abstract: This letter studies the physical-layer security of a multi-antenna transmission system in the presence of Poisson distributed eavesdroppers. The transmission secrecy outage probability (TSOP) is adopted to evaluate the security. We derive an accurate integral expression as well as a closed-form upper bound on TSOP for the noncolluding eavesdroppers' case and a closed-form solution for the colluding eavesdroppers' case, respectively. Based on these, we define a novel concept of security region to intuitively illustrate the security from a spatial perspective. We further analyze the impacts of various factors on the security, such as the number of transmit antennas, the node intensity, and the target secrecy rate.
TL;DR: A high rate space-time block coded spatial modulation scheme with cyclic structure (STBC-CSM) that allows for a low-complexity maximum-likelihood (ML) detector due to the orthogonality of Alamouti's STBC.
Abstract: A high rate space-time block coded spatial modulation scheme with cyclic structure (STBC-CSM) is presented in this letter. In the proposed STBC-CSM scheme, a pair of transmit antennas are chosen out of the total transmit antennas to send Alamouti's STBC, whose two signal symbols are drawn from two different constellations, and the antenna pairs activated in different codewords are moving cyclically along the total transmit antenna array. To exploit the diversity advantage of Alamouti's STBC, the optimization of STBC-CSM is given by maximizing its coding gain. Moreover, the proposed scheme allows for a low-complexity maximum-likelihood (ML) detector due to the orthogonality of Alamouti's STBC. The simulation results verify our theoretical analysis and demonstrate the performance advantages of our proposed STBC-CSM over the existing schemes such as STBC-SM, H-STBC-SM, CIOD-SM-H and SM.
TL;DR: In this paper, the authors proposed a novel random access (RA) scheme to increase the number of available preambles for the future M2M communication environment, which can accommodate a significantly larger number of machine nodes with much lower collision probability and shorter random access delay.
Abstract: We expect that the number of machine-to-machine (M2M) devices will rapidly increase in the near future due to a growing demand for a wide range of M2M applications such as e-health, public safety, surveillance, remote maintenance and control, and smart metering. Therefore, the future cellular networks should accommodate a large number of M2M devices and their random access (RA) requests at a specific time instant. In this letter, we propose a novel RA scheme to effectively increase the number of available preambles for the future M2M communication environment. The proposed scheme provides additional preambles by spatially partitioning a cell coverage into multiple group regions and reducing cyclic shift size in RA preambles. As a result, the proposed RA scheme can accommodate a significantly larger number of machine nodes with much lower collision probability and shorter random access delay, compared to a conventional RA scheme.
TL;DR: The simulation results show that the bit error ratio performance can be improved when employing the optimum dc bias obtained by the proposed numerical method.
Abstract: Selecting an appropriate direct current (dc) bias is crucial to obtain positive and low-peak-to-average-power-ratio electrical signals in the dc optical orthogonal frequency-division multiplexing (DCO-OFDM) system. In this letter, our goal is to propose an optimization strategy of dc bias under given lower and upper clipping bounds. We characterize the mean square error between the original signals and the clipped ones as the metric of clipping distortion. Finding the optimum dc bias can be formulated as a nonconvex optimization problem. However, the optimum dc bias can be obtained from a numerical method. The simulation results show that the bit error ratio performance can be improved when employing the optimum dc bias obtained by the proposed numerical method.
TL;DR: Maximum Utility Algorithm (MUA) is proposed, a few orders of magnitude faster approach that achieves 3/4 of the network lifetime obtained by the LP solution.
Abstract: This paper addresses the problem of maximizing the network lifetime of rechargeable Wireless Sensor Networks (WSNs) whilst ensuring all targets are monitored continuously by at least one sensor node. The objective is to determine a group of sensor nodes, and their wake-up schedule such that within a time interval, one subset of nodes are active whilst others enter the sleep state to conserve energy as well as recharge their battery. We propose a Linear Programming (LP) based solution to determine the activation schedule of sensor nodes whilst affording them recharging opportunities and at the same time ensures complete target coverage. The results show our LP solution achieves more than twice the performance in terms of network lifetime as compared to similar algorithms developed for finite battery WSNs. However, it is computationally expensive. We therefore propose Maximum Utility Algorithm (MUA), a few orders of magnitude faster approach that achieves 3/4 of the network lifetime obtained by our LP solution.
TL;DR: This letter proposes a parametric sparse multiple input multiple output (MIMO)-OFDM channel estimation scheme based on the finite rate of innovation (FRI) theory, whereby super-resolution estimates of path delays with arbitrary values can be achieved.
Abstract: This letter proposes a parametric sparse multiple input multiple output (MIMO)-OFDM channel estimation scheme based on the finite rate of innovation (FRI) theory, whereby super-resolution estimates of path delays with arbitrary values can be achieved. Meanwhile, both the spatial and temporal correlations of wireless MIMO channels are exploited to improve the accuracy of the channel estimation. For outdoor communication scenarios, where wireless channels are sparse in nature, path delays of different transmit-receive antenna pairs share a common sparse pattern due to the spatial correlation of MIMO channels. Meanwhile, the channel sparse pattern is nearly unchanged during several adjacent OFDM symbols due to the temporal correlation of MIMO channels. By simultaneously exploiting those MIMO channel characteristics, the proposed scheme performs better than existing state-of-the-art schemes. Furthermore, by joint processing of signals associated with different antennas, the pilot overhead can be reduced under the framework of the FRI theory.
TL;DR: A low-complexity sequential soft decision decoding algorithm is proposed, based on the successive cancellation approach, and it employs most likely codeword probability estimates for selection of a path within the code tree to be extended.
Abstract: The problem of efficient decoding of polar codes is considered. A low-complexity sequential soft decision decoding algorithm is proposed. It is based on the successive cancellation approach, and it employs most likely codeword probability estimates for selection of a path within the code tree to be extended.
TL;DR: Simulation results show that the proposed algorithm can enable network operators to support fair resource allocation for M2M traffic without jeopardizing QoS of H2H traffic.
Abstract: We propose an opportunistic user association for multi-service HetNets aiming to guarantee quality of service (QoS) of human-to-human (H2H) traffic while providing fair resource allocation for machine-to-machine (M2M) traffic. We classify H2H traffic as primary service and M2M traffic as secondary service. The opportunistic user association is formulated as an optimization problem, which can be resolved by Nash Bargaining Solution (NBS). Simulation results show that the proposed algorithm can enable network operators to support fair resource allocation for M2M traffic without jeopardizing QoS of H2H traffic.