Channel Error Rate Research Articles

Better goodness-of-fit statistics for coded FSK decoding

In previous papers we have considered fast-frequency hopping frequency shift keying. We have proposed a decoder with low error rate in channels with low signal to interference ratio. This decoder uses the Kolmogorov-Smirnov criterion statistics to differentiate transmitted codeword from others. In this paper we consider different goodness-of-fit criterion to improve the decoder error rate. We have discovered that the decoder based on the Barnett-Eison criterion have lower error rates in wideband interference scenario, while the one based on the Anderson criterion is better in case of narrowband interference.

Practical round-robin differential-phase-shift quantum key distribution

The security of quantum key distribution (QKD) relies on the Heisenberg uncertainty principle, with which legitimate users are able to estimate information leakage by monitoring the disturbance of the transmitted quantum signals. Normally, the disturbance is reflected as bit flip errors in the sifted key; thus, privacy amplification, which removes any leaked information from the key, generally depends on the bit error rate. Recently, a round-robin differential-phase-shift QKD protocol for which privacy amplification does not rely on the bit error rate (Sasaki et al 2014 Nature 509 475) was proposed. The amount of leaked information can be bounded by the sender during the state-preparation stage and hence, is independent of the behavior of the unreliable quantum channel. In our work, we apply the tagging technique to the protocol and present a tight bound on the key rate and employ a decoy-state method. The effects of background noise and misalignment are taken into account under practical conditions. Our simulation results show that the protocol can tolerate channel error rates close to 50% within a typical experiment setting. That is, there is a negligible restriction on the error rate in practice.

Degradasi Jaringan TD-LTE 2.300 – 2.400 MHz Akibat Interferens Alur-Waktu Silang

Indonesia has set the frequency band 2,300-2,400 MHz (3GPP band 40) as one of the frequency allocations for the TD-LTE mobile network. Consequently, the implementation of TD-LTE should pay attention to the phenomenon of Crossed Timeslot Interference (CTI) which can occur as a result of the operators’ uplink-downlink configurations. A work simulating the impact of CTI interference that occurs between two network operators having an adjacent spectrum allocation is developed. Network performance indicator is measured through the value of Bit Error Rate (BER) and throughput value of Physical Downlink Shared Channel (PDSCH). The results show that the CTI has caused a degeneration of BER leading to a reduction of throughput value of PDSCH by 15.29%. This work is expected to be a reference for Indonesian network operators to pay more attention to the phenomenon of CTI which could potentially cause degradation of TD-LTE network performance.

Optical Orbital Angular Momentum Demultiplexing and Channel Equalization by Using Equalizing Dammann Vortex Grating

A novel equalizing Dammann vortex grating (EDVG) is proposed as orbital angular momentum (OAM) multiplexer to realize OAM signal demultiplexing and channel equalization. The EDVG is designed by suppressing odd diffraction orders and adjusting the grating structure. The light intensity of diffraction is subsequently distributed evenly in the diffraction orders, and the total diffraction efficiency can be improved from 53.22% to 82%. By using the EDVG, OAM demultiplexing and channel equalization can be realized. Numerical simulation shows that the bit error rate (BER) of each OAM channel can decrease to 10-4 when the bit SNR is 22 dB, and the intensity is distributed over the necessary order of diffraction evenly.

A fuzzy-based mechanism for delay window adjustment to improve TCP performance in wireless multi-hop networks

TCP protocol was initially designed for wired networks to guarantee reliable data transfer. In wired networks, TCP assumes congestion if data packets are dropped. However, this assumption does not hold when the end-to-end path includes wireless links, where, high bit error rate (BER), shared medium and dynamic nature of the wireless channel may cause packet loss. This results in a severe degrade in performance of standard TCP in wireless networks. On the other hand, TCP cannot be changed fundamentally due to the large base of installation in the wired network. Delayed-ACK generation at the TCP receiver has been proposed to mitigate collision rate within wireless network. However, choosing appropriate delayed window size is an important issue. In this article, we propose a new delayed-ACK approach based on a fuzzy controller to improve TCP performance in wireless networks. The major advantage of our mechanism is reducing the overhead and the collision rate in multi-hop wireless networks. We also compare our proposal with some of well-known studies. Simulations results confirm good performance of our mechanism.

Estimation of Convolutional Interleaver Parameters in the Burst and BSC Channels

Blind estimation of interleaver parameters is one of the initial steps of non cooperative context. Some studies have been performed to obtain the convolutional interleaver parameters, however, in all existing works, it is assumed that the channel is error free or at least has a very low error rate. Recently, by considering received noisy data, Gauss-Jordan Elimination Through Pivoting (GJETP) algorithm is proposed to estimate the period of the block interleaver. In this paper, by considering the convolutional interleaver, at first, we derive the period of the convolutional interleaver by applying GJETP algorithm on the intercepted analytical matrix. Then by using the denoising method, the more accurate estimation of the code rate will be derived. Finally, dependent columns sets can be derived precisely and by computing the minimum distance of locations of dependent columns, the depth of the interleaver can be estimated. Compared with the case which does not use the denoising method, our proposed method estimates the convolutional interleaver more accurately. Simulation results show that the algorithm has good performance even if the channel error rate is high.

ARQ Technique with Aggressive Packet Combining Scheme for Variable Error Rate Channels to Reduce the Bandwidth and Power Consumption

ARQ Technique with Aggressive Packet Combining Scheme for Variable Error Rate Channels to Reduce the Bandwidth and Power Consumption

A MAP Decoder for TVB Codes on a Generalized Iyengar–Siegel–Wolf BPMR Markov Channel Model

We present a generalization of the Iyengar–Siegel–Wolf Markov channel model for bit-patterned media recording media to allow negative drift, and adapt the maximum a posteriori decoder for time-varying block codes to work on this generalized model while minimizing complexity. We also describe a method for designing near-optimal codes for this channel using simulated annealing, obtaining better performance than alternative designs. In concatenation with a (999, 888)16 low-density parity-check (LDPC) code, we achieve a frame error rate (FER) of $10^{-3}$ at a channel error rate that is $1.73\times $ higher than the best result with existing designs. A simple extension to include substitution errors allows the channel to approximate the dependent insertion, deletion, and substitution (DIDS) channel, with a decoding complexity that is $10\times $ lower than that of Wu and Armand’s RC2 decoder. The performance in the absence of burst errors is almost identical. When the DIDS channel includes burst substitution errors, our decoder performs worse than the RC2 decoder, but maintains its complexity advantage. For the same concatenated code, our decoder achieves an FER of $10^{-3}$ at a channel error rate that is $1.68\times $ lower than the RC2 decoder. Finally, simulation results show that our code designs improve on existing constructions for the DIDS channel.

Security analysis of BB84 protocol in the collective-rotation noise channel

Most of quantum cryptography protocols are designed under the ideal conditions without considering the impact of noise in actual communication; thus they may result in that the confidential information cannot be transmitted to the receiver accurately or eavesdroppers can steal the confidential information by mixing in noise. Therefore, analyzing the security of quantum cryptography protocols under noise conditions is of great significance. For the purpose of analyzing the security of quantum BB84 protocol in collective-rotation noise, firstly this paper introduces the quantum BB84 protocol, and considers the influence of environmental noise on it. An explanation should be stated that in a noise environment, the effects of noise and eavesdropping cannot be distinguished between each other. So the mechanism for which the error bit is simply used as the criterion to judge whether there exists eavesdropping in the BB84 protocol, cannot be used in the noise environment. The mechanism to judge whether there exists eavesdropping in quantum noise channel needs to be modified and improved for protecting the information. An initial qubit error rate can be set according to the noisy quantum channel. If the qubit error rate of the quantum communication channel is larger than that, it can be determined that the quantum channel is not secure and exists eavesdropping, no matter what the reason is. And on this basis, the collective-rotation noise model will be established in quantum channel by using the particle deflection model and distinguish the noise from the eavesdropping in quantum channel quantitatively, and the relationship of the amount of information that eavesdroppers can steal, the quantum bits error rate and the noise level will be analyzed by using the von Neumann entropy. Finally, the noise critical point will be calculated by using the collective noise model and the relationship between the amount of information that eavesdroppers can steal, at the quantum bits error rate, and the noise level. Through the analysis, we can know that in the existing noise level, the most of the eavesdropping can steal 25% of the key from the communication. However, the Eve's eavesdropping behavior will be detected, so that Alice and Bob will give up the current consultation key, and restart the key negotiation. This result shows that the quantum BB84 protocol is safe and secure in the collective-rotation noise channel. The research results of this paper will enrich the theory of quantum cryptography, and the innovation of security detection methods in quantum cryptographic protocols will help promote the process of practical quantum cryptography.

Channel-Adaptive Packetization Policy for Minimal Latency and Maximal Energy Efficiency

This article considers the problem of delay optimal bundling of the input symbols into transmit packets in the entry point of a wireless sensor network such that the link delay is minimized under an arbitrary arrival rate and a given channel error rate. The proposed policy exploits the variable packet length feature of contemporary communications protocols in order to minimize the link delay via packet length regularization. This is performed through concrete characterization of the end-to-end link delay for zero error tolerance system with First Come First Serve (FCFS)queuing discipline and Automatic Repeat Request (ARQ) retransmission mechanism. The derivations are provided for an uncoded system as well as a coded system with a given bit error rate. The proposed packetization policy provides an optimal packetization interval that minimizes the end-to-end delay for a given channel with certain bit error probability. This algorithm can also be used for near-optimal bundling of input symbols for dynamic channel conditions provided that the channel condition varies slowly over time with respect to symbol arrival rate. This algorithm complements the current network-based delay-optimal routing and scheduling algorithms in order to further reduce the end-to-end delivery time. Moreover, the proposed method is employed to solve the problem of energy efficiency maximization under an average delay constraint by recasting it as a convex optimization problem.

Adaptive video protection in large scale peer‐to‐peer video streaming over mobile wireless mesh networks

SummaryBecause video streaming over mobile handheld devices has been of great interest, the necessity of introducing new methods with low implementation cost and scalable infrastructures is a strong demand of the service. In particular, these requirements are present in popular wireless networks such as wireless mesh networks (WMN). Peer‐to‐peer (P2P) networks promise an efficient scalable network infrastructure for video streaming over wired and wireless networks. Limited resources of the peers in P2P networks and high error rate in wireless channels make it more challenging to run P2P streaming applications over WMNs. Therefore, it is necessary to design efficient and improved error protection methods in P2P video streaming applications over WMNs. In this paper, we propose a new adaptive unequal video protection method specially intended for large scale P2P video streaming over mobile WMNs. Using this method, different frames have different priorities in receivers along the recovery process. Moreover, we precisely and completely evaluate different aspects related to frame protection in these networks using five important performance metrics including video distortion, late arrival distortion, end‐to‐end delay, overhead and initial start‐up delay. The results obtained from a precise simulation in OMNeT++ show that the proposed adaptive method significantly outperforms other solutions by providing better video quality on mobile wireless nodes. Copyright © 2015 John Wiley & Sons, Ltd.

Data rate, path length and network contention trade-off in IEEE 802.11s mesh networks: A dynamic data rate selection approach

Most of the commercially available wireless routers are equipped with multi-rate support to adopt physical data rates based on the channel condition fluctuations. The recent studies in multi-rate support have shown that low data rates are more effective when the channel error rate is high. Because of the physical layer modulation and signal decoding issues, low data rates are sustainable for long transmission ranges. Therefore, for multi-hop mesh networks, low data rates may scale down the end-to-end path length towards the destination in terms of number of hops, resulting in less end-to-end forwarding delay. However, for a network with high traffic load, long transmission ranges may increase contention for channel access among the contending neighbors. This paper uses the diffusion approximation method of queuing analysis to study the trade-off among data rate, end-to-end path length and network contention in a multi-rate mesh network built over the IEEE 802.11s specifications. From the observations of the theoretical analysis, a distributed and localized rate adaptation scheme is proposed for IEEE 802.11s mesh networks, by augmenting the standard peer selection, channel access and forwarding protocols. The performance of the proposed rate adaptation protocol is evaluated and compared with existing rate adaptation protocols using simulation results.

Privacy-Preserving and Truthful Detection of Packet Dropping Attacks in Wireless Ad Hoc Networks

Link error and malicious packet dropping are two sources for packet losses in multi-hop wireless ad hoc network. In this paper, while observing a sequence of packet losses in the network, we are interested in determining whether the losses are caused by link errors only, or by the combined effect of link errors and malicious drop. We are especially interested in the insider-attack case, whereby malicious nodes that are part of the route exploit their knowledge of the communication context to selectively drop a small amount of packets critical to the network performance. Because the packet dropping rate in this case is comparable to the channel error rate, conventional algorithms that are based on detecting the packet loss rate cannot achieve satisfactory detection accuracy. To improve the detection accuracy, we propose to exploit the correlations between lost packets. Furthermore, to ensure truthful calculation of these correlations, we develop a homomorphic linear authenticator (HLA) based public auditing architecture that allows the detector to verify the truthfulness of the packet loss information reported by nodes. This construction is privacy preserving, collusion proof, and incurs low communication and storage overheads. To reduce the computation overhead of the baseline scheme, a packet-block-based mechanism is also proposed, which allows one to trade detection accuracy for lower computation complexity. Through extensive simulations, we verify that the proposed mechanisms achieve significantly better detection accuracy than conventional methods such as a maximum-likelihood based detection.

New Protocol of Aggressive Packet Combining Scheme: An Extension to Throughput Comparison

Aggressive Packet Combining (APC) scheme is well established for receiving correct packet in high error prone wireless link. In APC three copies of a packet are transmitted and receiver does bit wise majority decision to get the correct copy. The main research challenge in APC is that if two or more copies of the packet become erroneous at the particular bit location then majority logic fails to correct the error and also as three copies of packet are sent at a time, throughput degradation takes place at higher error rate channel. In this paper we propose a new method of correction in APC which will address the limitation which occurs in conventional APC. General Terms Throughput comparison

Adaptive Modulation and Coding for LTE Wireless Communication

Long Term Evolution (LTE) is the new upgrade path for carrier with both GSM/UMTS networks and CDMA2000 networks. The LTE is targeting to become the first global mobile phone standard regardless of the different LTE frequencies and bands use in other countries barrier. Adaptive Modulation and Coding (AMC) is used to increase the network capacity or downlink data rates. Various modulation types are discussed such as Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM). Spatial multiplexing techniques for 4×4 MIMO antenna configuration is studied. With channel station information feedback from the mobile receiver to the base station transmitter, adaptive modulation and coding can be applied to adapt to the mobile wireless channels condition to increase spectral efficiencies without increasing bit error rate in noisy channels. In High-Speed Downlink Packet Access (HSDPA) in Universal Mobile Telecommunications System (UMTS), AMC can be used to choose modulation types and forward error correction (FEC) coding rate.

Relative Intensity Noise Suppression of Spectrum-Sliced Channels Using Polarization-Independent Optical Modulators

Performances of spectrum-sliced channels are strongly affected by their relative intensity noise (RIN). We use polarization-independent optical modulators (PIOMs) for spectrum-sliced channels to suppress their RIN. The PIOM driven by a high sinusoidal voltage signal evenly redistributes optical frequency components in the spectral domain and reduces the RIN. It can be used at a broadband light source (BLS) output to produce spectrum-sliced channels having lower RIN values. Also, it can be used for each spectrum-sliced channel within each optical network unit (ONU). In our experiment, where 12.5-GHz-spaced spectrum-sliced channels are used in 1-GbE speed, the use of PIOM at the BLS output reduces the bit error rate (BER) of the spectrum-sliced channel by more than an order of magnitude. The use of PIOM within the ONU reduces the BER by approximately 3 orders of magnitude.

A Truthful Double Auction Mechanism for Hybrid Spectrums

Auctions have been widely studied as an efficient approach of allocating spectrum among secondary users in recent years. On the other side, a wide range of frequency bands could be available in a spectrum auction considering the current trend of deregulating wireless resources, therefore, channels provided by the primary users may reside in widely separated frequency bands, and due to the difference in propagation profile, would show significant heterogeneity in transmission range, channel error rate, path-loss, etc. Also, we can consider the channels with similar propagation and quality characteristics, for example, channels located in the same frequency band, are homogeneous and can be located in one spectrum type. Therefore, in this paper, we propose a double auction mechanism for both homogeneous and heterogeneous spectrums, called hybrid spectrums. The hybrid auction design has its own challenges, especially it also inherits the challenges related to heterogeneity. We prove that our auction design can not only solve the challenges caused by hybrid spectrums but also preserve three important economic aspects including truthfulness, budget balance and individual rationality. Also, we show that the proposed scheme increases spectrum utilization through spectrum reuse. Also, we offer a novel comprehensive grouping procedure to increase both the channel utilization and the seller satisfaction. Results from extensive simulation studies demonstrate good performance of the proposed algorithms on various auction metrics.

Optimal Cooperative Spectrum Sensing Under Faded and Bandwidth Limited Control Channels

Most of the cooperative spectrum sensing related research assumes system models with perfect control channel (i.e. with unlimited channel bandwidth and no channel errors). However, the assumption is not realistic and can lead to incorrect conclusions regarding the performance analysis of the cooperative spectrum sensing detection capabilities. This paper proposes a novel cooperative spectrum sensing framework that mitigates the imperfect control channel features, like the limited control channel bandwidth and error proneness, and achieves the detection performances of cooperative spectrum sensing under ideal control channel. It utilizes node clustering and multi-antenna spatial multiplexing (i.e. beamforming) and provides a generic framework that can be exploited by any cooperative spectrum sensing and fusion technique. The performance analysis shows that the proposed framework alleviates the control channel bandwidth limitation and significantly decreases the control channel error rate. The performance evaluation results also show that the proposed framework achieves the upper bound detection performances, i.e. achieves the same detection performances as the conventional cooperative spectrum sensing with ideal control channel.

Improvement in Channel Estimation and Error Rate Performance in Mobile Cooperative OFDM Systems with Intercarrier Interference

In mobile cooperative orthogonal frequency division multiplexing (OFDM) systems with amplify-and-forward (AF) relays, in which the source and relay terminals are moving, Doppler frequency might become very large due to the formation of double-hop channels, possibly causing very large intercarrier interference (ICI). Therefore, ICI mitigation technique capable of reducing the impact of high Doppler frequency is required. This paper reports the study of ICI mitigation technique that uses frequency domain equalizer (FDE) with improvements in three aspects, namely, better channel estimation using cubic-spline approximation, use of selection combining to utilize cooperative diversity in order to suppress ICI, and simple error correcting code with double interleaving to suppress errors due to residual ICI. By using the proposed ICI mitigation technique, error rate performance of mobile cooperative OFDM systems can be improved significantly. Even at high Doppler frequencies, error floors due to residual ICI can be decreased by up to two decades.

Skew angle effects in shingled magnetic recording system with double/triple reader head array

Shingled Magnetic Recording (SMR) is a scheme used to extend the life of the current perpendicular magnetic recording technology. SMR enables writing narrow tracks with a wide writer. Currently, SMR employs a single reader and will suffer inter-track interference (ITI) as the tracks become comparable in width to the reader. ITI can be mitigated by using narrower readers; however, narrower readers suffer from increased reader noise. Another approach to combat ITI is to process 2D readback and use ITI cancellation schemes to retrieve the data track. Multiple readbacks can be obtained either with a single reader and multiple revolutions or with a reader array. The former suffers from increased readback latency. In this work, we focus on the latter. When using a reader array, the skew angle poses major challenges. During writing, there is increased adjacent track erasure, and during readback the effective reader pitch varies and there is an increase in the 2D intersymbol interference caused by the rotated reader profile. In this work, we run micromagnetic simulations at different skew angles to train the grain flipping probability model, and then evaluate raw bit channel error rate performance at skew. In particular, we investigate the performance degradation caused by skewing of the 2 or 3 read head array for various read-head geometries.